Deck 2: Motion

Question 1

The pound is an English unit of measure; its SI counterpart is the

A)newton.
B)kilogram.
C)joule.
D)momentum.

Answer 1

A

Question 2

The attractive force a 70-kg person exerts on Earth is much, much smaller than the force Earth exerts on the person.

Answer 2

False

Question 3

A car traveling at 20 mph on a curved exit ramp has a constant velocity.

Answer 3

False

Question 4

When you roll a ball across the floor, it comes to a stop because you are no longer exerting a force on it.

Question 5

An object accelerates when it slows or its direction of movement changes.

Question 6

Suppose that a rock is swinging in a circle when some string is let out so that the length doubled as the same speed is maintained.The force now exerted on the string is

A)the same as before.
B)doubled.
C)half as great.
D)four times as great.

Question 7

In the equation represents

A)average speed.
B)instantaneous speed.
C)final speed.
D)constant speed.

Question 8

Imagine an experiment in which a 8-lb bowling ball and a 10-lb bowling ball are dropped from the fifth floor at the same time.The heavier ball will reach the ground first.

Question 9

A heavy object and a light object are dropped from rest at the same time in a vacuum.The heavier object will reach the ground

A)before the lighter object.
B)at the same time as the lighter object.
C)after the lighter object.
D)It depends on the shape of the object.

Question 10

The weight of a 50-kg box is closest to

A)5 N.
B)50 N.
C)500 N.
D)5000 N.

Question 11

The reason a moving object slows down is that its force of motion gradually runs out.

Question 12

The newton is a unit of

A)motion.
B)energy.
C)power.
D)force.

Question 13

Gravity is an attractive force between

A)all massive objects.
B)Earth and objects on Earth.
C)Earth and Moon, and objects on Earth.
D)all objects everywhere.

Question 14

Newton's second law states that if an unbalanced force acts on an object, it will move at constant velocity.

Question 15

Astronauts experience a weightless condition when they are in orbit.

Question 16

The force of gravity near the surface of Earth is 9.8 m/s².

Question 17

The tendency of a moving object to remain in unchanging motion in the absence of an unbalanced force is called

A)inertia.
B)free fall.
C)acceleration.
D)impulse.

Question 18

A boy on a skateboard pushes off the ground with his foot.He and the skateboard accelerate down the sidewalk due to the force

A)he exerts against the ground.
B)between the skateboard wheels and the ground.
C)the ground exerts against his foot.
D)of gravity acting on the skateboard.

Question 19

The momentum of an object remains the same unless an unbalanced force acts on it.

Question 20

Ignoring air resistance, the velocity of a falling object

A)is constant.
B)is constantly increasing.
C)increases for a while, then becomes constant.
D)depends on the mass of the object.

Question 21

A block of iron is transported to the Moon.Which of the following is true?

A)both its mass and weight remain unchanged.
B)its mass decreases, but its weight remains the same.
C)its mass remains the same, but its weight decreases.
D)both its mass and weight decrease.

Question 22

Everything that happens in the universe can be traced to interactions of

A)matter and gravity.
B)light and matter.
C)four fundamental forces.
D)gravity waves and light.

Question 23

You should "follow through" when hitting a ball because

A)this increases the force.
B)momentum is conserved.
C)of the relationship $\Delta$ p = Ft.
D)momentum is mv.

Question 24

From the equation w = mg, it is apparent that weight is a (an)

A)force.
B)mass.
C)acceleration.
D)None of the above.

Question 25

If you consider the total distance and total time for a trip, you are calculating a (an)

A)instantaneous speed.
B)constant speed.
C)average speed.
D)non-uniform speed

Question 26

A 250-g ball travels at a velocity of 40 m/s.Its momentum is

A)4 kg·m/s.
B)10 kg·m/s.
C)160 kg·m/s.
D)10,000 kg·m/s.

Question 27

The mass of a 100-N sack of seed is closest to

A)10 kg.
B)10 lb.
C)98 kg.
D)1,000 kg.

Question 28

If an unbalanced force applied to an object doubles, then

A)its velocity doubles.
B)its acceleration doubles.
C)its acceleration is cut in half.
D)its acceleration increases by a factor of four.

Question 29

If you double the mass of an object while an unbalanced force remains constant,

A)the object moves at half the speed.
B)the acceleration of the object is doubled.
C)the object will gradually slow down.
D)The acceleration of the object is halved.

Question 30

A cannon ball and a bowling ball were dropped at the same time from the top of a building.At the instant before the balls hit the sidewalk, the cannon ball has greater

A)velocity.
B)acceleration.
C)momentum.
D)All of these are the same for the two balls.