When adding two numbers, the number of significant figures in the sum is equal to the number of significant figures in the least accurate of the numbers being added.
False
When determining the number of significant figures in a number, zeroes to the left of the decimal point are never counted.
False
0.0001776 can also be expressed as
1.776 x 10^-4
The number 0.00310 has
4 significant figures
What is the sum of 1.53 + 2.786 + 3.3 written with the correct number of significant figures
7.6
The following exact conversion equivalents are given: 1m=100cm, 1 in= 2.54 cm, and 1ft=12 in. If a computer screen has an area of 1.27ft^2, this area is closest to
0.118 m^2
The shortest wavelength of visible light is approximately 400nm. Express this wavelength in centimeters.
4 x 10^-5 cm
1nm = 1 x 10^7 cm
The wavelength of a certain laser is 0.35 micrometers, where 1 micrometer = 1 x 10^-6 nm. Express this wavelength in nanometers.
3.5 x 10^2 nm
1m = 1 x 10^9 nm
A certain CD-ROM disk can store approximately 6.0 x 10^2 megabytes of information, where 10^6 bytes = 1 megabyte. If can average word requires 9.0 bytes or storage, how many words can be stored on one disk?
6.7 x 10^7 words
Consider a deer that runs from point A to point B. The distance the deer runs can be greater than the magnitude of its displacement, but the magnitude of the displacement can never be greater than the distance it runs.
True
Suppose that an object travels from one point in space to another. Make a comparison between the magnitude of the displacement and the distance traveled by this object.
The displacement is either less than or equal to the distance traveled.
If the velocity of an object is zero at some point, then its acceleration must also be zero at that point.
False
If the acceleration of an object is zero, then that object cannot be moving.
False
An object moving in the +x direction experiences an acceleration of 2.0m/s^2. This means the object
is increasing its velocity by 2.0m/s every second.
Suppose that an object is moving with a constant velocity. Which statement concerning its acceleration must be correct?
The acceleration is equal to zero.
A ball is thrown straight up, reaches maximum height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration of the ball as it is going up is correct?
Its velocity points upward and its acceleration points downwards.
A racing car accelerates uniformly from rest along a straight track. This track has markers spaced at equal distances along it from the start, as shown in the figure. The car reaches a speed of 140 km/h as it passes marker 2.
Where on the track was the ca
Before marker 1
A ball is thrown downward in the absence of air resistance. After it has been released, which statement(s) concerning its acceleration is correct?
Its acceleration is constant.
Ball A is dropped from the top of a building. One second later, ball B is dropped from the same building. Neglect air resistance. As time progresses the difference in their speeds
Remains constant
From the edge of a roof top you toss a green ball upwards with initial speed v0 and a blue ball downwards with the same initial speed. Air resistance is negligible. When they reach the ground below
The two balls will have the same speed
A car initially traveling at 60 km/h accelerates at constant rate of 2.0 m/s^2. How much time is required for the car to reach a speed of 90 km/h?
4.2 seconds
An airplane increases speed at the average rate of 15 m/s^2. How much time does it take to increase its speed from 100 m/s to 160 m/s?
4.0 seconds
A cart with an initial velocity of 5.0 m/s to the right experiences a constant acceleration of 2.0 m/s^2 to the right. What is the cart's displacement during the first 6.0 seconds of this motion?
66 m
Brick A is dropped from the top of a building. Brick B is thrown straight down from the same building, and neither one experiences appreciable air resistance. Which statement about their accelerations is correct?
The two bricks have exactly the same acceleration
If a vector pointing upward has a positive magnitude, a vector pointing downward has a negative magnitude.
False
Two displacement vectors have magnitudes of 5.0 m and 7.0 m, respectively. If these two vectors are added together, the magnitude of the sum
could be as small as 2.0 m or as large as 12 m
Two vectors, of magnitudes 20 mm and 50 mm, are added together. Which one of the following is a possible value for their magnitude of the resultant?
40 mm
If vectors A+B=C and their magnitudes are given by A + B = C, then the vectors A and B are oriented
Parallel to each other (in the same direction)
The magnitude of a vector can never be less than the magnitude of any of its components.
True
If a vector A has components Ax < 0, and Ay > 0, then the angle that this vector makes with the positive x-axis must be in the range
90 degrees to 180 degrees
The eastward component of vector A is equal to the westward component of vector B and their northward components are equal. Which one of the following statements must be correct for these two vectors?
The magnitude of vector A must be equal to the magnitude of vector B
Vector A is along the +x-axis and vector B is along the +y-axis. Which one of the following statements is correct with respect to these vectors?
...
For general projectile motion with no air resistance, the horizontal component of a projectile's velocity
Remains a non-zero constant
For general projectile motion with no air resistance, the horizontal component of a projectile's acceleration
Is always zero
For general projectile motion with no air resistance, the vertical component of a projectile's acceleration
Remains a non-zero constant
A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically. Which object is traveling faster when it hits the level ground below if neither of them experiences any air resistance?
The ball
James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below if there i
James and John will reach the surface of the lake at the same time
A player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory
Neither the ball's velocity nor its acceleration are zero
A rock is thrown down from the upper edge of a tall cliff at some angle above the horizontal. It reaches its highest point and starts falling down. Which of the following statements about the rock's motion are true just before it hits the ground? (There c
Its horizontal velocity component is the same as it was just as it was launched
A small car and a large SUV are at a stoplight. The car has a mass equal to half that of the SUV, and the SUV can produce a maximum accelerating force equal to twice that of the car. When the light turns green, both drivers push their accelerators to the
It is a tie
An object is moving with constant non-zero velocity. Which of the following statements about it must be true?
The new force on the object is zero
The x component of vector A is 8.7 units, and its y component is -6.5 units. The magnitude of A is closest to
11 units
The x component of vector A is 5.3 units, and its y component is -2.3 units. The angle that vector A makes with the +x-axis is closest to
23 degrees
You push on box G that is next to box H, causing both boxes to slide along the floor, as shown in the figure. The reaction force to your push is
The push of box G against you
A box is placed on a table which rests on the floor. The box pushes on the table; the reaction force to the box's push on the table is the table's push on the floor.
False
If you pound a feather with a hammer, which one feels a greater force?
If the feather moves, then it felt the greater force. Otherwise the force was the same on both.
While flying horizontally in an airplane, you notice that a string dangling from the overhead luggage compartment hangs at rest at 15 degrees away from the vertical toward the front of the place. Using this observation, you can conclude that the airplane
Accelerating backward.
A bucket is being lowered by a very high rope with a constant downward velocity. The tension in the rope must be
Equal to the weight of the bucket
Bill and his daughter Susan are both standing on identical skateboards (with really good frictionless ball bearings), initially at rest. Bill weighs three times as much as Susan. Bill pushes horizontally on Susan's back, causing Susan to start moving away
Susan and Bill are moving away from each other, and Susan's speed is three times that of Bill
A truck is using a hook to tow a car whose mass is one quarter that of the truck. If the force exerted by the truck on the car is 6000N, then the force exerted by the car on the truck is
6000N
An object of weight W is in free fall close to the surface of Earth. The magnitude of the force that the object exerts on Earth is
Equal to W
You are standing in a moving bus, facing forward, when you suddenly slide forward as the bus comes to an immediate stop. What force caused you to slide forward?
There is not a force causing you to slide forward
A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical frictional force that the pole exerts on the fireman. When the force on his hands equals his weight, what happens to the fireman?
The fireman continues to descend, but with constant speed.
A person who normally weighs 700 N is riding in a rather swift elevator that is moving at a constant speed of 9.8 m/s. If this person is standing on a bathroom scale inside the elevator, what would the scale read?
700 N
A person who normally weighs 700 N is riding in an elevator that is moving upward but slowing down at a steady rate. If this person is standing on a bathroom scale inside the elevator, what would the scale read?
Less than 700 N
Inside of a train a ball of weight W is hanging by a light wire at rest from the ceiling. The wire makes an angle with the ceiling, as shown in the figure. Which one of the following conditions must be true about the tension T in the wire?
T sin(theta) =W
A push of magnitude P acts on a box of weight W as shown in the figure. The push is directed at an angle below the horizontal, and the box remains at rest. The box rests on a horizontal surface that has some friction with the box. The friction force on th
P cos(theta)
Two boxes are connected to each other by a string as shown in the figure. The 10-N box slides without friction on the horizontal table surface. The pulley is ideal and the string has negligible mass. What is true about the tension T in the string?
T > 30 N
A block of mass m sits as rest on a rough inclined ramp that makes an angle with the horizontal. What must be true about the force of static friction F on the block?
f = mg sin(theta)
A block of mass m sits at rest on a rough inclined ramp that makes an angle with the horizontal. What must be true about normal force F on the block due to the ramp?
F = mg cos(theta)
Two objects have masses m and 5m, respectively. They both are placed side by side on a frictionless inclined ramp and allowed to slide down from rest without any air resistance. Which one of the following statements about these objects is correct?
The two objects reach the bottom of the ramp at exactly the same time.
On its own, a tow truck has a maximum acceleration of 3.0 m/s^2. What will be its maximum acceleration when the truck is using a light horizontal chain to tow a bus of twice its own mass?
1.0 m/s^2
A 450-kg sports car accelerates from rest to 100 km/h in 4.80s. What magnitude force does a 68.0 kg passenger experience during the acceleration?
394 N
An object that weighs 75 N is pulled on a horizontal surface by a horizontal pull of 50 N to the right. The friction force on this object is 30 N to the left. What is the acceleration of the object?
2.6 m/s^2
When an object moves in uniform circular motion, the direction of its acceleration is
Directed toward the center of its circular path
Two small objects, with masses m and M, are originally a distance r apart, and the magnitude of the gravitational force on each one is F. The masses are changed to 2m and 2M, and the distance is changed to 4r. What is the magnitude of the new gravitationa
F/4
Two small objects, with masses m and M, are originally a distance r apart, and the gravitational force on each one has magnitude F. The second object has its mass changed to 2M, and the distance is changed to r/4. What is the magnitude of the new gravitat
32F
A spaceship is traveling to the Moon. At what point is it beyond the pull of Earth's gravity?
It is never beyond the pull of Earth's gravity
If you stood on a planet having a mass four times that of Earth's mass, and a radius two times that of Earth's radius, you would weigh
The same as you do on Earth
A hypothetical planet has a mass of one-half that of the earth and a radius of twice that of the earth. What is the acceleration due to gravity on the planet in terms of g, the acceleration due to gravity at the surface of the earth?
g/8
Two planets have the same surface gravity, but planet B has twice the radius of planet A. If planet A has mass m, what is the mass of planet B?
4m
Planet A has twice the mass of Planet B. From this information, what can we conclude about the acceleration due to gravity at the surface of Planet A compared to that at the surface of planet B?
We cannot conclude anything about the acceleration due to gravity on Planet A without knowing the radii of the two planets
A 250-kg motorcycle goes around an unbanked turn of radius 13.7 m at a steady 96.5 km/h. What is the magnitude of the net force on the motorcycle?
1.31 x 10^4 N
At their closest approach, Venus and Earth are 4.20 x 10^10 m apart. The mass of Venus is 4.87 x 10^24, the mass of Earth is 5.97 x 10^24 kg, and G = 6.67 x 10^-11 Nm^2/kg^2. What is the magnitude of the gravitational force exerted by Venus on Earth at th
1.10 x 10^18 N
When a car goes around a circular curve on a horizontal road at constant speed, what force causes it to follow the circular path?
The friction force from the road
Person X pushes twice as hard against a stationary brick wall as person Y. Which one of the following statements is correct?
Both do zero work
A 35-N bucket of water is lifted vertically 3.0 m and then returned to its original position. How much work did gravity do on the bucket during this process?
0 J
Which one has larger kinetic energy: a 500-kg object moving at 40 m/s or a 1000-kg object moving at 20 m/s?
The 500-kg object
Three cars (car F, car G, and car H) are moving with the same speed and slam on their brakes. The most massive car is car F, and the least massive is car H. If the tires of all three cars have identical coefficients of kinetic friction with the road surfa
They all travel the same distance in stopping
Three cars (car F, car G, and car H) are moving with the same speed and slam on their brakes. The most massive car is car F, and the least massive is car H. If the tires of all three cars have identical coefficients of kinetic friction with the road surfa
Car F
A 4.0 kg object is moving with speed 2.0 m/s. A 1.10 kg object is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?
Both objects travel the same distance
Which requires more work, increasing a car's speed from 0 mph to 30 mph or from 50 mph to 60 mph?
50 mph to 60 mph
A stone is held at a height h above the ground. A second stone with 4 times the mass of the first one is held at the same height. The gravitational potential energy of the second stone compared to that of the first stone is
Four times as much
You and your friend, who weighs the same as you, want to go to the top of the Eiffel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. Compare the gravitational potential energy of you an
Both of you have the same amount of gravitational potential energy at the top.
A heavy dart and a light dart are launched horizontally on a frictionless table by identical ideal springs. Both springs were initially compressed by the same amount. Which of the following statements about these darts are correct? (There could be more th
The darts both have the same kinetic energy just as they move free of the spring
The lighter dart leaves the spring moving faster than the heavy dart
Both darts had the same initial elastic potential energy
When you throw a pebble straight up with initial speed V, it reaches a maximum height H with no air resistance. At what speed should you throw it up vertically so it will go twice as high?
square root of 2V
When you drop a pebble from height H, it reaches the ground with speed V if there is no air resistance. From what height should you drop it so it will reach the ground with twice speed?
4H
When you drop a pebble from height H, it reaches the ground with kinetic energy K if there is no air resistance. From what height should you drop it so it will reach the ground with twice as much kinetic energy?
2H
Two objects, one of mass m and other of mass 2m, are dropped from the top of a building. If there is no air resistance, when they hit the ground
The heavier one will have twice the kinetic energy of the lighter one
Swimmers at a water park have a choice of two frictionless water slides, as shown in the figure. Although both slides drop over the same height h, slide 1 is straight while slide 2 is curved, dropping quickly at first and then leveling out. How does the s
v1 = v2
A person stands on the edge of a cliff. She throws three identical rocks with the same speed. Rock X is thrown vertically upward, rock Y is thrown horizontally, and rock Z is thrown vertically downward. If the ground at the base of the cliff is level, whi
They all hit the around with the same speed
Two identical grasshoppers jump into the air with the same initial speed and experience no air resistance. Grasshopper A goes straight up, but grasshopper B goes up at a 66-degree angle above the horizontal. Which of the following statements about these g
At their highest point, both of them have the same amount of mechanical energy
At their highest point, grasshopper B is moving faster than grasshopper A
At their highest point, grasshopper A has more gravitational potential energy than grasshopper B
Jill does twice as much work as Jack does and in half the time. Jill's power output is
Four times Jack's power output
A force produces power P by doing work W in a time T. What power will be produced by a force that does six times as much work in half as much time?
12P
Which of the following quantities are units of momentum? (There could be more than one correct choice.)
kg(m/s)
N(s)
A very elastic rubber ball is dropped from a certain height and hit the floor with a downward speed v. Since it is so elastic, the ball bounces back with the same speed v going upward. Which of the following statements about the bounce are correct?
The magnitude of the ball's momentum was the same just before and just after the bounce
The momentum of an isolated system is conserved
In both elastic and inelastic collisions
A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the momentum change during the collision is correct? (There could be more than one correct choice.)
The small car and the truck experience the same magnitude momentum change
A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average force during the collision is correct?
The small car and the truck experience the same average force
In an inelastic collision involving an isolated system, the final total momentum is
exactly the same as the initial momentum
A 5-kg ball collides inelastically head-on with a 10-kg ball, which is initially stationary. Which of the following statements is true? (There could be more than one correct choice.)
The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball
The magnitude of the change of the momentum of the 5-kg ball equal to the magnitude of the change of momentum of the 10-kg ball
In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is
Elastic
An egg falls from a bird's nest in a tree and feels no effects due to the air. As it falls,
Only its mechanical energy is conserved
A railroad car collides with and sticks to an identical railroad car that is initially at rest. After the collision, the kinetic energy of the system
Is half as much as before
On a horizontal frictionless air table, a puck runs into an ideal horizontal spring that is fastened to the table. The puck compresses the spring by 15 cm before coming to rest. During the compression process, which quantities are conserved?
The momentum and the mechanical energy of the puck
Two objects of different mass have equal, non-zero kinetic energies. Which object as the greater magnitude momentum?
The heavier object
Two objects of different masses have momentum of equal, non-zero magnitude. Which object has more kinetic energy?
The lighter object
If you want to double the momentum of a gas molecule, by what factor must you increase its kinetic energy?
4
When a rigid object rotates about a fixed axis, what is true about all the points in the object? (There could be more than one correct choice.)
They all have the same angular speed
They all have the same angular acceleration
Two children, Ahmed and Jacques, ride on a merry-go-round. Ahmed is at a greater distance from the axis or rotation than Jacques. Which of the following are true statements?
Jacques and Ahmed have the same angular speed
A disk and a hoop of the same mass and radius are released at the same time at the top of an inclined plane. If both are uniform, which one reaches the bottom of the incline first if there is no slipping?
The disk
A disk, a hoop, a solid sphere are released at the same time at the top of an inclined plane. They are all uniform and roll without slipping. In what order do they reach the bottom?
Sphere, disk, hoop
Two equal-magnitude forces are applied to a door at the doorknob. The first force is applied perpendicular to the door, and the second force is applied at 30 degrees to the plane of the door. Which force exerts the greater torque about the door hinge?
The first force (applied perpendicular to the door)
As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest?
2
Five forces act on a rod that is free to pivot at point P, as shown in the figure. Which of these forces is producing a counter-clockwise torque about point P? (There could be more than one correct choice.)
Force C
A merry-go-round spins freely when Diego moves quickly to the center along a radius of the merry-go-round. As he does this, it is true to say that
The moment of inertia of the system decreases and the angular speed increases
A spinning ice skater on extremely smooth ice is able to control the rate at which she rotates by pulling in her arms. Which of the following statements are true about the skater during this process? (There could be more the one correct choice.)
Her angular momentum remains constant
What is the angular speed, in rad/s, of a flywheel turning at 813.0 rpm?
85.14 rad/s
If the sum of the external forces on an object is zero, then the sum of the external torques on it must be zero.
False
If the sum of both the external torques and the external forces on an object is zero, then the object must be at rest.
True
If an object remains at rest, then the sum of both the external torques and the external forces on the object must be zero.
True
Substance A has a density of 3 g/cm^3 and substance B has a density of 4 g/cm^3. In order to obtain equal masses of these two substances, what must be the ratio of the volume of A to the volume of B?
VA/VB = 4/3
As shown in the figure, flood fills a container having several sections. At which of the indicated points is the pressure greatest?
The pressure is the same at each of the labeled points
Consider a brick that is totally immersed in water, with the long edge of the brick vertical. The pressure on the brick is
Greatest on the bottom of the brick
An air bubble underwater has the same pressure as that of the surrounding water. As the air bubble rises toward the surface (and its temperature remains constant), the volume of the air bubble
Increases
Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat?
The buoyant force is the same in both cases
Salt water is denser than fresh water. A ship floats in both fresh water and salt water. Compared to the fresh water, the volume of water displaced in the salt water is
Less
A 10-kg piece of aluminum sits at the bottom of a lake, right next to a 10-kg piece of lead, which is much denser than aluminum. Which one has the greater buoyant force on it?
The aluminum
A piece of iron rests on top of a piece of wood floating in a bathtub. If the iron is removed from the wood, and kept out of the water, what happens to the water level in the tub?
It goes down
A plastic block of dimensions 2.00 cm x 3.00 cm x 4.00 cm has a mass of 30.0 g. What is its density?
1.25 g/cm^3
A block made from certain material has a density that equals to that of water. If it is placed fully submerged in a tank of water and released, it will
Rise to the surface
If we double the frequency of a system undergoing simple harmonic motion, which of the following statements about that system are true?
The period is reduced to one-half of what it was
A simple harmonic oscillator oscillates with frequency f when its amplitude is. If the amplitude is now doubled to 2A, what is the new frequency?
f
In a simple harmonic motion, when is the speed the greatest? (There could be more than one correct choice.)
When the magnitude of the acceleration is a minimum
The total mechanical energy of a simple harmonic oscillation system is
A non-zero constant
A mass on a spring undergoes SHM. When the mass is at its maximum distance from the equilibrium position, which of the following statements about it are true?(There could be more than one correct choice.)
Its kinetic energy is maximum
An object is attached to a vertical spring and bobs up and down between points A and B. Where is the object located when its kinetic energy is a minimum?
At either A or B
An object is attached to a vertical spring and bobs up and down between points A and B. Where is the object located when its kinetic energy is a maximum?
Midway between A and B
Two simple pendulums, A and B, are each 3.0 m long, and the period of pendulum A is T. Pendulum A is twice as heavy as pendulum B. What is the period of pendulum B?
T/2
Identical balls oscillate with the same period T on Earth. Ball A is attached to an ideal spring and ball B swings back and forth to form a simple pendulum. These systems are now taken to the Moon, where g = 1.6 m/s^2, and set into oscillation. Which of t
On the moon, ball B will take longer to complete one cycle than ball A
What is the frequency of the wave shown in the figure?
0.5 Hz
A simple pendulum oscillates with period T on Earth. If the whole setup is taken to the Moon, how does the period change?
Period will not change
A cannon sits on a stationary railroad flatcar with total mass of 1000 kg. When a 10-kg cannon ball is fired to the left at a speed of 50 m/s, what is the recoil speed of the flatcar?
0.5 m/s to the right
How does the work required to stretch a spring 2 cm compare with the work required to stretch it 1 cm?
4 times the work
Is it possible for the gravitational potential energy of an object to be negative?
Yes
Is it possible for the elastic potential energy of an object to be negative?
No
A projectile is launched from the ground at an angle of 30 degrees. At what point in its trajectory does this projectile have the least speed?
At the highest point in its flight
You drop a package from a plane flying at constant speed in a straight line. Without air resistance, the package will
Remain vertically under the plane while falling
Consider a cart on a horizontal frictionless table. Once the cart has been given a push and released, what will happen to the cart?
Continues with constant velocity
To convert from cm^2 to m^2, you should
Multiply by 1/10,000
1 cm^2= 0.0001 m^2
Suppose you pull a simple pendulum to one side by an angle of 5 degrees, let go, and measured the period of oscillation that ensues. Then you stop the oscillation, pull the pendulum to an angle of 10 degrees, and let go. The resulting oscillation will hav
The same as
Which of the following increases the speed of waves in a stretched elastic cord? (More than one answer may apply.)
Stretching the elastic cord further
A wave transports
Energy but not matter
What happens when two waves, such as waves on a lake, come from different directions and run into each other?
They may have various patterns where they overlap, but each wave continues with its original pattern away from the region of overlap
Why does an ocean liner float?
The average density of the ocean liner is less than that of seawater
Hot air is less dense than cold air. Could a hot-air balloon be flown on the Moon, where there is no atmosphere?
No, there is no cold air to displace, so no buoyancy force would exist
An object that can float in both water and in oil (whose density is less than that of water experiences a buoyant force that is
The same when it is floating in water or in oil
When you apply the torque equation to an object in equilibrium, the axis about which torques are calculated
Can be located anywhere
Two children are balanced on opposite sides of a seesaw. If one child leans inward toward the pivot point, her side will
Rise
A 60-kg woman stands on the very end of a uniform board, of length l, which is supported one-quarter of the way from one end and is balanced. What is the mass of the board?
60 kg
An object at rest begins to rotate with a constant angular acceleration. If this object rotates through an angle in time t, through what angle did you rotate in the time 1/2t?
1/4(theta)
Two spheres have the same radius and equal mass. One sphere is solid, and the other is hollow and made of a denser material. Which one has the bigger moment of inertia about an axis through its center?
The hollow one
Two wheels having the same radius and mass rotate at the same angular. One wheel is made with spokes so nearly all the mass is at the rim. The other is a solid disk. How does their rotational kinetic energies compare?
The wheel with spokes has about twice the KE
If you used 1000 J of energy to throw a ball, would it travel faster if you threw the ball (ignoring air resistance)
So that it wasn't rotating
A small solid sphere and a small thin hoop are rolling along a horizontal surface with the same translational speed when they encounter a 20 degree rising slope. If these two objects roll up the slope without slipping, which will rise farther up the slope
The hoop
A small mass m on a string is rotating without friction in a circle. The string is shortened by pulling it through the axis of rotation without any external torque. What happens to the tangential velocity of the object?
It increases
A truck going 15 km/h has a head-on collision with small car going 30 km/h. Which statement best describes the situation?
They both have the same change in magnitude of momentum because momentum is conserved
A small boat coasts at constant speed under a bridge. A heavy sack of sand is dropped from the bridge onto the boat. The speed of the boat
Decreases
A space shuttle, in circular orbit around the Earth, collides with a small asteroid which ends up in the shuttle's storage bay. For this collision,
Only momentum is conserved
You are lying in bed and want to shut your bedroom door. You have a bouncy "superball" and a blob of clay, both with the same mass. Which one would be more effective to throw at your door to close it?
The superball
A satellite in circular orbit around the Earth moves at constant speed. This orbit is maintained by the force of gravity between the Earth and the satellite, yet no work is done on the satellite. How is this possible?
No work is done if the direction of motion is perpendicular to the force
You push very hard on a heavy desk, trying to move it. You do work on the desk:
Only if it starts moving
A ball is thrown straight up. Neglecting air resistance, which statement is not true regarding the energy of the ball?
The potential energy decreases while the ball is going up
Which of the following point towards the center of the circle in uniform circular motion?
Acceleration, net force
A child whirls a ball in a vertical circle. Assuming the speed of the ball is constant (an approximation), when would the tension in the cord connected to the ball be greatest?
At the bottom of the circle
A space shuttle in orbit around the Earth carries its payload with its mechanical arm. Suddenly, the arm malfunctions and releases the payload. What will happen to the payload?
It will remain in the same orbit with the shuttle
A truck is traveling horizontally to the right. When the truck starts to slow down, the crate on the (frictionless) truck bed starts to slide. In what direction could the net force be on the crate?
No direction. The net force is zero
You are trying to push your stalled car. Although you apply a horizontal force of 400 N to the car, it doesn't budge, and neither do you. Which force(s) must also have magnitude of 400 N?
The friction force exerted by the road on you
You are pushing a heavy box across a rough floor. When you are initially pushing the box and it is accelerating,
The force you exert on the box is equal to the force of the box pushing back on you
A 50-N crate sits on a horizontal floor where the coefficient of static friction between the crate and the floor is 0.50. A 20-N force is applied to the crate acting to the right. What is the resulting static friction force acting on the crate?
20 N to the left
Suppose an object is accelerated by a force of 100 N. Suddenly a second force of 100 N in the opposite direction is exerted on the object, so that the forces cancel. The object
Continues at the velocity it had before the second force was applied
A golf ball is hit with a golf club. While the ball flies through the air, which forces act on the ball? Neglect air resistance.
The force of gravity acting on the ball
One ball is dropped vertically from a window. At the same instant, a second ball is thrown horizontally from the same window. Which ball has the greater speed at ground level?
The thrown ball
You are riding an enclosed train car moving 90 km/h. If you throw a baseball straight up, where will the baseball land?
In your hand
A baseball is hit high and far. Which of the following statements is true? At the highest point,
The magnitude of the velocity is the slowest
Which statements are not valid for a projectile? Take up as positive.
The acceleration of the projectile is positive and decreasing when the projectile is moving upwards, zero at the top, and increasingly negative as the projectile descends
The velocity at the highest point is zero
A displacement vector is 34.0 m in length and is directed 60.0 degrees east of north. Selecting from the choices in the table below, what are the components of this vector?
Northward Component- 29.4 m
Eastward Component- 17.0 m
A rubber ball bounces off of a wall with an initial speed v and reverses its direction so its speed is v right after the bounce. As a result of this bounce, which of the following quantities of the ball are conserved?
The kinetic energy of the ball
When is the angular momentum of a system constant?
Only when no external torque acts on the system
If the sum of the external torques on an object is zero, then the sum of the external forces on it must also be zero.
False
A mass oscillates in SHM with period T on Earth. If the whole setup is taken to the Moon, how does the period change?
Period will not change