Two masses collide and stick together. Before the collision one of the masses was at rest. Is there a situation in which the kinetic energy is conserved in such a collision?
d. No, kinetic energy is always lost is such a collision.
Two masses m1 and m2, with m1 = 3 m2, undergo a head-on elastic collision. If the particles were approaching with speed v before the collision, with what speed are they moving apart after collision?
d. v
The dimensional equivalent of the quantity impulse in terms of the fundamental quantities (mass, length, time) is which of the following?
a. MLT-1
A 0.12-kg ball is moving at 6 m/s when it is hit by a bat, causing it to reverse direction and have a speed of 14 m/s. What is the change in the magnitude of the momentum of the ball?
d. 2.4 kgm/s
Alex throws a 0.15-kg rubber ball down onto the floor. The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s. If the ball is in contact with the floor for 0.025 s, what is the magnitude of the average force applied by the floor on the
a. 60 N
Jerome pitches a baseball of mass 0.20 kg. The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Jerome with a return speed of 60 m/s. What is the magnitude of change in the ball's momentum?
d. 20 kgm/s
A ball with original momentum +4.0 kgm/s hits a wall and bounces straight back without losing any kinetic energy. The change in momentum of the ball is:
d. -8.0 kgm/s.
If a glass of water is on a table with a piece of paper under it, it is relatively easy to pull the paper out without disturbing the glass very much if the pull is done very quickly. This is because, with a quick pull:
c. the time for the pull will be less.
The units of impulse are equivalent to:
c. kg*m/s.
A 75-kg swimmer dives horizontally off a 500-kg raft. If the diver's speed immediately after leaving the raft is 4 m/s, what is the corresponding raft speed?
c. 0.6 m/s
A cannon of mass 1 500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 45 above the horizontal. Find the recoil velocity of the cannon across the level ground.
b. 0.94 m/s
A machine gun is attached to a railroad flatcar that rolls with negligible friction. If the railroad car has a mass of 6.25 104 kg, how many bullets of mass 25 g would have to be fired at 250 m/s off the back to give the railroad car a forward velocity o
d. 5 000
Ann the Astronaut weighs 60 kg. She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s. What speed does this give Ann as she moves toward the shuttle?
b. 5.3 m/s
If the momentum of an object is tripled, its kinetic energy will change by what factor?
d. nine
The kinetic energy of an object is quadrupled. Its momentum will change by what factor?
b. two
A moderate force will break an egg. However, an egg dropped on the road usually breaks, while one dropped on the grass usually doesn't break. This is because for the egg dropped on the grass:
c. the time interval for stopping is greater.
A 20-g bullet moving at 1 000 m/s is fired through a one-kg block of wood emerging at a speed of 100 m/s. If the block had been originally at rest and is free to move, what is its resulting speed?
b. 18 m/s
2 600 rev/min is equivalent to which of the following?
c. 273 rad/s
A 0.12-m-radius grinding wheel takes 5.5 s to speed up from 2.0 rad/s to 11.0 rad/s. What is the wheel's average angular acceleration?
c. 1.6 rad/s2
A ceiling fan is turned on and reaches an angular speed of 120 rev/min in 20 s. It is then turned off and coasts to a stop in an additional 40 s. The ratio of the average angular acceleration for the first 20 s to that for the last 40 s is which of the fo
d. -2
A 0.30-m-radius automobile tire rotates how many rad after starting from rest and accelerating at a constant 2.0 rad/s2 over a 5.0-s interval?
b. 25 rad
A fan blade, initially at rest, rotates with a constant acceleration of 0.025 rad/s2. What is the time interval required for it to reach a 4.2-rad displacement after starting from rest?
d. 18 s
Starting from rest, a wheel undergoes constant angular acceleration for a period of time T. At what time after the start of rotation does the wheel reach an angular speed equal to its average angular speed for this interval?
b. 0.50 T
Starting from rest, a wheel undergoes constant angular acceleration for a period of time T. At which of the following times does the average angular acceleration equal the instantaneous angular acceleration?
d. all of the above
A ventilation fan has blades 0.25 m in radius rotating at 20 rpm. What is the tangential speed of each blade tip?
b. 0.52 m/s
A 0.30-m-radius automobile tire accelerates from rest at a constant 2.0 rad/s2 over a 5.0-s interval. What is the tangential component of acceleration for a point on the outer edge of the tire during the 5-s interval?
c. 0.60 m/s2
Consider a point on a bicycle wheel as the wheel makes exactly four complete revolutions about a fixed axis. Compare the linear and angular displacement of the point.
c. Only the linear displacement is zero.
Consider a point on a bicycle wheel as the wheel turns about a fixed axis, neither speeding up nor slowing down. Compare the linear and angular velocities of the point.
b. Only the angular velocity is constant.
A 0.30-m-radius automobile tire accelerates from rest at a constant 2.0 rad/s2. What is the centripetal acceleration of a point on the outer edge of the tire after 5.0 s?
c. 30 m/s2
A 0.150-m-radius grinding wheel, starting at rest, develops an angular speed of 12.0 rad/s in a time interval of 4.00 s. What is the centripetal acceleration of a point 0.100 m from the center when the wheel is moving at an angular speed of 12.0 rad/s?
c. 14.4 m/s2
A vault is opened by applying a force of 300 N perpendicular to the plane of the door, 0.80 m from the hinges. Find the torque due to this force about an axis through the hinges.
b. 240 Nm
Two children seat themselves on a seesaw. The one on the left has a weight of 400 N while the one on the right weighs 300 N. The fulcrum is at the midpoint of the seesaw. If the child on the left is not at the end but is 1.50 m from the fulcrum and the se
c. -600 N�m
The quantity "moment of inertia" (in terms of the fundamental quantities of mass, length, and time) is equivalent to:
c. ML^2.
A 4.0-kg mass is placed at (3.0, 4.0) m, and a 6.0-kg mass is placed at (3.0, -4.0) m. What is the moment of inertia of this system of masses about the x-axis?
a. 160 kg�m^2
If a net torque is applied to an object, that object will experience
If a net torque is applied to an object, that object will experience
According to Newton's second law, the angular acceleration experienced by an object is directly proportional to:
b. the net applied torque.
A ventilation fan with a moment of inertia of 0.034 kgm2 has a net torque of 0.11 Nm applied to it. What angular acceleration does it experience?
c. 3.2 rad/s2
The Earth moves about the Sun in an elliptical orbit. As the Earth moves closer to the Sun, which of the following best describes the Earth Sun system's moment of inertia?
a. decreases
A bowling ball has a mass of 7.0 kg, a moment of inertia of 2.8 102 kgm2 and a radius of 0.10 m. If it rolls down the lane without slipping at a linear speed of 4.0 m/s, what is its angular speed?
d. 40 rad/s
A solid sphere with mass, M, and radius, R, rolls along a level surface without slipping with a linear speed, v. What is the ratio of rotational to linear kinetic energy? (For a solid sphere, I = 0.4 MR2).
d. 2/5
Samantha pushes a 50-N crate up a ramp 25.0 m in length and inclined at 10 with the horizontal. What potential energy change does the crate experience?
d. 220 J
A 40-kg boy is standing on the edge of a stationary 30-kg platform that is free to rotate. The boy tries to walk around the platform in a counterclockwise direction. As he does:
c. the platform rotates in a clockwise direction while the boy goes around in a counterclockwise direction relative to the ground.
The total kinetic energy of a baseball thrown with a spinning motion is a function of:
c. both linear and rotational speeds.
A bowling ball has a mass of 7.0 kg, a moment of inertia of 2.8 102 kgm2 and a radius of 0.10 m. If it rolls down the lane without slipping at a linear speed of 4.0 m/s, what is its total kinetic energy?
d. 78 J
A solid sphere of mass 4.0 kg and radius 0.12 m is at rest at the top of a ramp inclined 15. It rolls to the bottom without slipping. The upper end of the ramp is 1.2 m higher than the lower end. Find the sphere's total kinetic energy when it reaches the
b. 47 J
A solid sphere with mass, M, and radius, R, rolls along a level surface without slipping with a linear speed, v. What is the ratio of rotational to linear kinetic energy? (For a solid sphere, I = 0.4 MR2).
d. 2/5
An object of mass 0.50 kg is transported to the surface of Planet X where the object's weight is measured to be 20 N. The radius of the planet is 4.0 106 m. What is the mass of Planet X? (G = 6.67 1011 N m2/kg2)
c. 9.6 x 1024 kg
An object when orbiting the Earth at a height of three Earth radii from the center of the Earth has a weight of 1.00 N. What is the object's mass? (g at the surface of the Earth is 9.8 m/s2)
c. 0.92 kg
If the mass of Mars is 0.107 times that of Earth, and its radius is 0.530 that of Earth, estimate the gravitational acceleration g at the surface of Mars. (gearth = 9.80 m/s2)
b. 3.73 m/s2
At what location does an artificial Earth satellite in elliptical orbit have its greatest speed?
a. nearest the Earth