The speedometer of an automobile reads
Instantaneous speed
If the net force acting on a moving object is zero, the object will
Continuous moving at a constant speed
Which of the following is a vector quantity?
NOT mass, volume, or time
What does Galileo discover in his legendary experiment on the Leaning Tower of Pisa?
Found that a heavier stone does not fall significantly faster than a lighter one
If a car increases its velocity from 0 to 60 m/s in 10 seconds, its acceleration is
60 m/s^2
When a pair of 10-N forces act on a box of candy, the net force on the box is
Need more information
Compared to the mass of an apple on Earth, the mass of the apple on the Moon is
one sixth as much
When a baseball player bats a ball with a force of 1000 N, the reaction force that the ball exerts against the bat is
1000 N
A block of ice is sliding across a frozen pond at a constant velocity. If surfaces are friction-less and air resistance can be neglected, the pushing force required to keep it sliding at a constant velocity is
No pushing force is required to keep it moving
A vehicle undergoes acceleration when it
changes it direction, gains speed, loses speed
A freely falling object starts from rest. What's its instantaneous speed in 4 seconds
40 m/s
What exactly is meant by a "freely falling" object?
An object under free fall falls under gravity alone
A mosquito is flying at 3 m/s. When it encounters a breeze blowing at 2 m/s in the opposite direction, what's its speed relative to the ground?
3 m/s
While a car travels around a circular track at a constant speed, its
neither is zero (velocity & acceleration)
A sheet a paper can be quickly jerked beneath a container of milk without toppling, which best demonstrates
inertia
A ball starting from rest at the top of an inclined plane gains a speed of 2 m/s for each second it rolls. What is its acceleration down the incline?
2 m/s ^2
Jogging Jake runs at 4 m/s on a train flatcar that moves at 10 m/s in the same direction. Jake's speed relative to the ground is
14 m/s
A ball is thrown straight upwards. If air resistance is negligible, compared with its initial speed, its speed when it returns to the same location is
about the same
An apple is in non-free fall. Before it reaches its terminal speed, which of the following is decreasing as it's falling down
Its acceleration
A package falls off a truck that is moving at 30 m/s. The horizontal speed of the package just before it hits the ground is
about 30 m/s
Harry pulls on the end of a spring attached to a wall. The reaction to Harry's pull on the spring is
the spring pulling on Harry
A stone is thrown straight upward in the air. At one instant it is moving upward at 50 m/s. One second later its speed is approximately
40 m/s
A car by itself is capable of a certain maximum acceleration. When it tows a twice-as-massive car, its maximum acceleration is
one third
A heavy block is pulled straight upwards by a rope. If the block is accelerating upward, the rope tension
is greater than its weight
A light woman and a heavy man jump from an airplane at the same time and open their same- size parachutes at the same time. Which person will reach terminal speed first?
The light woman
A boulder following a straight-line path at constant speed has
zero acceleration
A hummingbird flying at 4 km/h that gets caught in a 3-km/h crosswind has a resultant speed of
5 km/h
While you stand on the floor you are pulled downward by gravity, and supported upward by the floor. The downward gravity and the upward support force on you
do not make an action-reaction pair of forces
Suzie Skydiver, who weighs 500 N, reaches terminal speed of 90 km/h. The air resistance on Suzie is then
500 N
If you toss a coin straight upward in a train that is gaining speed quickly, the coin will land
behind you
If the net force of an object is somehow tripled, the acceleration of the object will be
tripled
The normal force that acts on a block of ice that slides on a ramp
decreases as the slope of the ramp increases
If a stone falls from the top to the bottom of a mine shaft in 6 s, the depth of the shaft is about
180 m
Which of the following has zero acceleration? An object
in mechanical equilibrium, moving at a constant velocity, and at rest
The mass of a lamb that weighs 110 N on Earth is about
11 kg
From the experiment on inclined planes, Galileo
developed the concept of acceleration, discovered the concept of inertia, found that a ball rolling on an inclined plane had constant acceleration
When you exert a horizontal pushing force on a crate that is on a level floor but the crate does NOT move, how great is the force of friction on the crate?
the friction is equal to your push
A 10-kilogram block is pushed across a level surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block is then
1 m/s^2
When you drop a flat sheet of paper and an identical but crumpled sheet of paper at the same time from the same height in the classroom, which one will hit the ground first?
the crumpled one
A rock is thrown vertically upward into the air. At the top of its path the net force on it is
mg