Question 1

A 2500-N pile driver ram falls 10 m and drives a post 0.1 m into the ground. The average force on the post is

Accepted Answer

A) 2500 N. 
B) 25,000 N. 
C) 250,000 N. 
D) 2,500,000 N. 
A) 2500 N. 
B) 25,000 N. 
C) 250,000 N. 
D) 2,500,000 N.

Question 2

A sandbag is motionless in outer space. A second sandbag with 3 times the mass moving at 12 m/s collides with it and they both stick together and move at a speed of

Accepted Answer

A) 3 m/s. 
B) 4 m/s. 
C) 6 m/s. 
D) 8 m/s. 
E) none of the above 
A) 3 m/s. 
B) 4 m/s. 
C) 6 m/s. 
D) 8 m/s. 
E) none of the above

Question 3

A jack system will increase the potential energy of a heavy load by no more than 1000 J with a work input of 2000 J. The efficiency of the jack system is at most

Accepted Answer

A) 10%. 
B) 20%. 
C) 50%. 
D) 80%. 
E) not enough information 
A) 10%. 
B) 20%. 
C) 50%. 
D) 80%. 
E) not enough information

Question 4

Which requires more work on the brakes of a car?

Accepted Answer

A) slowing down from 100 km/h to 70 km/h 
B) slowing down from 70 km/h to a stop 
C) equal amounts of work for either 
A) slowing down from 100 km/h to 70 km/h 
B) slowing down from 70 km/h to a stop 
C) equal amounts of work for either

Question 5

Suppose you are at the edge of a cliff and you throw one ball downward and another ball upward at the same speed. Which will hit the ground faster? Does direction of the thrown ball make a difference? Explain.

Accepted Answer

According to the conservation of energy,

Question 6

If you push for an hour against a stationary wall, you do no work

Accepted Answer

A) on the wall. 
B) at all. 
C) both 
D) none of the above 
A) on the wall. 
B) at all. 
C) both 
D) none of the above

Question 7

Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m?

Accepted Answer

A) lifting the 50-kg sack 
B) lifting the 25-kg sack 
C) both require the same amount of work 
A) lifting the 50-kg sack 
B) lifting the 25-kg sack 
C) both require the same amount of work

Question 8

The most underlying feature of machines is

Accepted Answer

A) the conservation of energy. 
B) that energy input always equals energy output. 
C) that power input always equals power output. 
D) all of the above 
E) none of the above 
A) the conservation of energy. 
B) that energy input always equals energy output. 
C) that power input always equals power output. 
D) all of the above 
E) none of the above

Question 9

The source of Earth's internal energy involves

Accepted Answer

A) kinetic energy. 
B) potential energy. 
C) radioactivity. 
D) the Sun. 
A) kinetic energy. 
B) potential energy. 
C) radioactivity. 
D) the Sun.

Question 10

A 1000-kg car and a 2000-kg car are hoisted the same distance in a service station. Raising the more massive car requires

Accepted Answer

A) less work. 
B) as much work. 
C) twice as much work. 
D) four times as much work. 
E) more than four times as much work. 
A) less work. 
B) as much work. 
C) twice as much work. 
D) four times as much work. 
E) more than four times as much work.

Question 11

The massive ram of a pile driver falling from rest strikes a pile with a speed that depends on the

Accepted Answer

A) initial height of the ram. 
B) initial potential energy of the ram. 
C) distance the ram falls. 
D) all of the above 
A) initial height of the ram. 
B) initial potential energy of the ram. 
C) distance the ram falls. 
D) all of the above

Question 12

An unfortunate bug splatters on the windshield of a moving car. Describe the forces, impulses, momentum changes, and accelerations of both the bug and the car.

Accepted Answer

According to Newton's third law, the for

Question 13

Which of these forms of energy is NOT renewable?

Accepted Answer

A) wind power 
B) solar power 
C) fossil fuel power 
D) photovoltaic power 
A) wind power 
B) solar power 
C) fossil fuel power 
D) photovoltaic power

Question 14

A karate expert executes a swift blow and severs a brick with her bare hand. Equal magnitudes occur for the

Accepted Answer

A) impulse on both the brick and the expert's hand. 
B) force on both the brick and the expert's hand. 
C) time of contact on both the block and the expert's hand. 
D) all of the above 
E) none of the above 
A) impulse on both the brick and the expert's hand. 
B) force on both the brick and the expert's hand. 
C) time of contact on both the block and the expert's hand. 
D) all of the above 
E) none of the above

Question 15

A rifle of mass 2 kg is horizontally suspended by a pair of strings so that recoil can be measured. The rifle fires a bullet of mass 1/100 kg at a speed of 200 m/s. The recoil velocity of the rifle is about

Accepted Answer

A) 0.001 m/s. 
B) 0.01 m/s. 
C) 0.1 m/s. 
D) 1 m/s. 
E) none of the above 
A) 0.001 m/s. 
B) 0.01 m/s. 
C) 0.1 m/s. 
D) 1 m/s. 
E) none of the above

Question 16

If you do work on an object in half the time, your power output is

Accepted Answer

A) half. 
B) the same. 
C) twice. 
A) half. 
B) the same. 
C) twice.

Question 17

Why does the force of gravity do no work on a bowling ball rolling along a bowling alley lane?

Accepted Answer

Work is done on an object only when a fo

Question 18

When the input piston of a hydraulic press is depressed 20 cm, the output piston is observed to move 1 cm. An input force of 1 N can raise no more than

Accepted Answer

A) 1 N. 
B) 10 N. 
C) 20 N. 
D) 21 N. 
A) 1 N. 
B) 10 N. 
C) 20 N. 
D) 21 N.

Question 19

A car traveling along the highway needs a certain amount of braking force to stop. More braking force is required when the car has

Accepted Answer

A) more mass. 
B) more momentum. 
C) less stopping distance. 
D) all of the above 
E) none of the above 
A) more mass. 
B) more momentum. 
C) less stopping distance. 
D) all of the above 
E) none of the above

Question 20

The conservation of momentum is closely related to

Accepted Answer

A) Newton's first law. 
B) Newton's second law. 
C) Newton's third law. 
A) Newton's first law. 
B) Newton's second law. 
C) Newton's third law.

Exam 3: Momentum and Energy

A 2500-N pile driver ram falls 10 m and drives a post 0.1 m into the ground. The average force on the post is

A sandbag is motionless in outer space. A second sandbag with 3 times the mass moving at 12 m/s collides with it and they both stick together and move at a speed of

A jack system will increase the potential energy of a heavy load by no more than 1000 J with a work input of 2000 J. The efficiency of the jack system is at most

Which requires more work on the brakes of a car?

Suppose you are at the edge of a cliff and you throw one ball downward and another ball upward at the same speed. Which will hit the ground faster? Does direction of the thrown ball make a difference? Explain.

If you push for an hour against a stationary wall, you do no work

Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m?

The most underlying feature of machines is

The source of Earth's internal energy involves

A 1000-kg car and a 2000-kg car are hoisted the same distance in a service station. Raising the more massive car requires

The massive ram of a pile driver falling from rest strikes a pile with a speed that depends on the

An unfortunate bug splatters on the windshield of a moving car. Describe the forces, impulses, momentum changes, and accelerations of both the bug and the car.

Which of these forms of energy is NOT renewable?

A karate expert executes a swift blow and severs a brick with her bare hand. Equal magnitudes occur for the

A rifle of mass 2 kg is horizontally suspended by a pair of strings so that recoil can be measured. The rifle fires a bullet of mass 1/100 kg at a speed of 200 m/s. The recoil velocity of the rifle is about

If you do work on an object in half the time, your power output is

Why does the force of gravity do no work on a bowling ball rolling along a bowling alley lane?

When the input piston of a hydraulic press is depressed 20 cm, the output piston is observed to move 1 cm. An input force of 1 N can raise no more than

A car traveling along the highway needs a certain amount of braking force to stop. More braking force is required when the car has

The conservation of momentum is closely related to

Patterns of Motion and Equilibrium

Newtons Laws of Motion

Gravity, Projectiles, and Satellites

Fluid Mechanics

Thermal Energy and Thermodynamics

Heat Transfer and Change of Phase

Static and Current Electricity

Magnetism and Electromagnetic Induction

Waves and Sound

Light

Atoms and the Periodic Table

The Atomic Nucleus and Radioactivity

Elements of Chemistry

How Atoms Bond and Molecules Attract

Mixtures

How Chemicals React

Two Classes of Chemical Reactions

Organic Compounds

Rocks and Minerals

Plate Tectonics and Earths Interior

Shaping Earths Surface

Geologic Timereading the Rock Record

The Oceans, Atmosphere, and Climatic Effects

Driving Forces of Weather

The Solar System

Stars and Galaxies

The Structure of Space and Time

Prologue: the Nature of Science

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