Question 1

A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 s. The speed of the car just before the brakes were applied was

Accepted Answer

A) 1)2 m/s. 
B) 15 m/s. 
C) 30 m/s. 
D) 45 m/s. 
E) none of the above 
A) 1)2 m/s. 
B) 15 m/s. 
C) 30 m/s. 
D) 45 m/s. 
E) none of the above C

Question 2

An empty roller coaster car at an amusement park takes 3 min to make its ride from start to finish. Neglecting friction, a fully loaded car would take

Accepted Answer

A) less than 3 min. 
B) more than 3 min. 
C) 3 min. 
A) less than 3 min. 
B) more than 3 min. 
C) 3 min. C

Question 3

A jumbo jet has a mass of 100,000 kg. The thrust for each of four engines is 50,000 N. What is the jet's acceleration in meters per second squared when taking off?

Accepted Answer

A) 0)25 
B) 1 
C) 2 
D) 4 
E) none of the above 
A) 0)25 
B) 1 
C) 2 
D) 4 
E) none of the above C

Question 4

A force of 1 N accelerates a mass of 1 kg at the rate of 1 m/s2. The acceleration of a mass of 2 kg acted upon by a force of 2 N is

Accepted Answer

A) half as much. 
B) twice as much. 
C) the same. 
D) none of the above 
A) half as much. 
B) twice as much. 
C) the same. 
D) none of the above

Question 5

A car traveling at 100 km/h strikes an unfortunate bug and splatters it. The force of impact is greater on the

Accepted Answer

A) bug. 
B) car. 
C) same for both 
A) bug. 
B) car. 
C) same for both

Question 6

A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The impact force is greatest on the

Accepted Answer

A) Volkswagen. 
B) Mack truck. 
C) same for both 
A) Volkswagen. 
B) Mack truck. 
C) same for both

Question 7

A pair of tennis balls fall through the air from a tall building. One ball is ordinary and the other is filled with lead pellets. Air resistance just before they hit the ground is actually greater for the

Accepted Answer

A) regular ball. 
B) lead-filled ball. 
C) same for both 
A) regular ball. 
B) lead-filled ball. 
C) same for both

Question 8

Strictly speaking, why will an object in free-fall not experience terminal velocity as it falls?

Accepted Answer

To say an object is in free-fa

Question 9

If you are driving at 20 m/s and slam on your brakes and skid at 0.5 g to a full stop, the skidding time in seconds is about

Accepted Answer

A) 3) 
B) 4) 
C) 5) 
D) 6) 
E) more than 6. 
A) 3) 
B) 4) 
C) 5) 
D) 6) 
E) more than 6.

Question 10

A physicist says that a car moving along a level road is being propelled by the road. Defend this statement.

Accepted Answer

It's true. The tires are made to rotate

Question 11

A falling skydiver of mass 100 kg experiences 500-N air resistance. The acceleration of the skydiver is

Accepted Answer

A) 0)2 g. 
B) 0)3 g. 
C) 0)4 g. 
D) 0)5 g. 
E) more than 0.5 g. 
A) 0)2 g. 
B) 0)3 g. 
C) 0)4 g. 
D) 0)5 g. 
E) more than 0.5 g.

Question 12

The human body can, under certain conditions, withstand an acceleration of 10g. What net force would produce this acceleration on a 50-kg person?

Accepted Answer

A) about 500 N 
B) about 2500 N 
C) about 5000 N 
D) about 25,000 N 
E) none of the above 
A) about 500 N 
B) about 2500 N 
C) about 5000 N 
D) about 25,000 N 
E) none of the above

Question 13

A horse exerts 500 N of force on a heavy wagon. The wagon pulls back on the horse with an equal force. The wagon still accelerates because

Accepted Answer

A) these forces are not an action-reaction pair. 
B) there is nevertheless still an unbalanced force on the wagon. 
C) the horse pulls on the wagon a brief time before the wagon reacts. 
D) the wagon does not accelerate because these forces are equal and opposite. 
E) unlike the horse, it is not alive. 
A) these forces are not an action-reaction pair. 
B) there is nevertheless still an unbalanced force on the wagon. 
C) the horse pulls on the wagon a brief time before the wagon reacts. 
D) the wagon does not accelerate because these forces are equal and opposite. 
E) unlike the horse, it is not alive.

Question 14

By gliding, an animal can

Accepted Answer

A) gain forward thrust. 
B) better control its fall. 
C) reduce its inertia. 
D) fly at reduced speed. 
A) gain forward thrust. 
B) better control its fall. 
C) reduce its inertia. 
D) fly at reduced speed.

Question 15

In the absence of air drag, why will a rock and a pebble accelerate equally when dropped?

Accepted Answer

They accelerate equally becaus

Question 16

The force required to maintain an object at a constant velocity in free space is equal to

Accepted Answer

A) zero. 
B) the mass of the object. 
C) the weight of the object. 
D) the force required to stop it. 
E) none of the above 
A) zero. 
B) the mass of the object. 
C) the weight of the object. 
D) the force required to stop it. 
E) none of the above

Question 17

A player hits a ball with a bat. The action force is the impact of the bat against the ball. The reaction to this force is the

Accepted Answer

A) air resistance on the ball. 
B) weight of the ball. 
C) force of the ball against the bat. 
D) grip of the player's hand against the ball. 
E) none of the above 
A) air resistance on the ball. 
B) weight of the ball. 
C) force of the ball against the bat. 
D) grip of the player's hand against the ball. 
E) none of the above

Question 18

A heavy rock and a light rock in free-fall have the same acceleration. The reason the heavy rock doesn't have a greater acceleration is that the

Accepted Answer

A) force due to gravity is the same on each. 
B) air resistance is always zero in free fall. 
C) inertia of both rocks is the same. 
D) ratio of force to mass is the same. 
E) none of the above 
A) force due to gravity is the same on each. 
B) air resistance is always zero in free fall. 
C) inertia of both rocks is the same. 
D) ratio of force to mass is the same. 
E) none of the above

Question 19

When you drop a ball, it accelerates due to Earth's gravity. How does it accelerate if you instead throw it downward? Explain.

Accepted Answer

It has the same acceleration whether dro

Question 20

A large person and a small person wish to parachute at equal terminal velocities. The larger person will have to

Accepted Answer

A) get a larger parachute. 
B) jump lightly. 
C) pull upward on the supporting strands to decrease the downward net force. 
D) jump first from the plane. 
E) none of the above 
A) get a larger parachute. 
B) jump lightly. 
C) pull upward on the supporting strands to decrease the downward net force. 
D) jump first from the plane. 
E) none of the above

Exam 3: Newtons Laws of Motion

A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 s. The speed of the car just before the brakes were applied was

An empty roller coaster car at an amusement park takes 3 min to make its ride from start to finish. Neglecting friction, a fully loaded car would take

A jumbo jet has a mass of 100,000 kg. The thrust for each of four engines is 50,000 N. What is the jet's acceleration in meters per second squared when taking off?

A force of 1 N accelerates a mass of 1 kg at the rate of 1 m/s2. The acceleration of a mass of 2 kg acted upon by a force of 2 N is

A car traveling at 100 km/h strikes an unfortunate bug and splatters it. The force of impact is greater on the

A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The impact force is greatest on the

A pair of tennis balls fall through the air from a tall building. One ball is ordinary and the other is filled with lead pellets. Air resistance just before they hit the ground is actually greater for the

Strictly speaking, why will an object in free-fall not experience terminal velocity as it falls?

If you are driving at 20 m/s and slam on your brakes and skid at 0.5 g to a full stop, the skidding time in seconds is about

A physicist says that a car moving along a level road is being propelled by the road. Defend this statement.

A falling skydiver of mass 100 kg experiences 500-N air resistance. The acceleration of the skydiver is

The human body can, under certain conditions, withstand an acceleration of 10g. What net force would produce this acceleration on a 50-kg person?

A horse exerts 500 N of force on a heavy wagon. The wagon pulls back on the horse with an equal force. The wagon still accelerates because

By gliding, an animal can

In the absence of air drag, why will a rock and a pebble accelerate equally when dropped?

The force required to maintain an object at a constant velocity in free space is equal to

A player hits a ball with a bat. The action force is the impact of the bat against the ball. The reaction to this force is the

A heavy rock and a light rock in free-fall have the same acceleration. The reason the heavy rock doesn't have a greater acceleration is that the

When you drop a ball, it accelerates due to Earth's gravity. How does it accelerate if you instead throw it downward? Explain.

A large person and a small person wish to parachute at equal terminal velocities. The larger person will have to

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