A 400 kg vehicle is travelling in outer space at a speed of 200 m/s. The smallest constant force that must be applied to stop it in 20 seconds is

A 400 kg vehicle is travelling in outer space at a speed of 200 m/s. The smallest constant force that must be applied to stop it in 20 seconds is 

A) 160 N.
B) 800 N.
C) 40 N.
D) 4000 N.







Answer: D

A skydiver falls towards the Earth. The attraction of the Earth on the diver pulls the diver down. What is the reaction to this force?

A skydiver falls towards the Earth. The attraction of the Earth on the diver pulls the diver down. What is the reaction to this force? 

A) air resistance the diver encounters while falling
B) water resistance that will soon act upward on the diver
C) the attraction to the planets, stars, and every particle in the universe
D) all of these
E) none of these

Answer: E

A baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is

A baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is 

A) less than 1000 N.
B) more than 1000 N.
C) 1000 N.
D) impossible to determine.






Answer: C

Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of massless rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of

Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of massless rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of 

A) 3 m.
B) 4 m.
C) 6 m.
D) 0 m.







Answer: B

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the 

A) combined weight of the arrow and bowstring.
B) air resistance against the bow.
C) friction of the ground against the archer's feet.
D) grip of the archer's hand on the bow.
E) arrow's push against the bowstring.

Answer: E

Wherever there is an action force, there must be a reaction force that

Wherever there is an action force, there must be a reaction force that 

A) always acts in the same direction.
B) is slightly smaller in magnitude than the action force.
C) is slightly larger in amplitude than the action force.
D) is exactly equal in magnitude.







Answer: D

A feather and a coin will have equal accelerations when falling in a vacuum because

A feather and a coin will have equal accelerations when falling in a vacuum because 

A) their velocities are the same.
B) the force of gravity is the same for each in a vacuum.
C) the force of gravity does not act in a vacuum.
D) the ratio of each object's weight to its mass is the same.
E) none of these

Answer: D

A skydiver, who weighs 500 N, reaches terminal velocity of 90 km/h. The air resistance on the diver is then

A skydiver, who weighs 500 N, reaches terminal velocity of 90 km/h. The air resistance on the diver is then 

A) 90 N.
B) 250 N.
C) 410 N.
D) 500 N.
E) none of these








Answer: D

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity 

A) the object accelerates in the direction of the applied force.
B) the object accelerates opposite the direction of the applied force.
C) the friction force increases.
D) two of the above
E) none of the above








Answer: A

If an object of constant mass experiences a constant net force, it will have a constant

If an object of constant mass experiences a constant net force, it will have a constant 

A) velocity.
B) speed.
C) acceleration.
D) position.
E) more than one of the above






Answer: C

A 2000-kg car experiences a braking force of 8,000 N and skids to a stop in 5 seconds. The speed of the car just before the brakes were applied was

A 2000-kg car experiences a braking force of 8,000 N and skids to a stop in 5 seconds. The speed of the car just before the brakes were applied was 

A) 20 m/s.
B) 1.25 m/s.
C) 300 m/s.
D) 45 m/s.
E) none of these






Answer: A

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

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 

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







Answer: B

A skydiver of mass 100 kg experiences air resistance of 600 N, and an acceleration of

A skydiver of mass 100 kg experiences air resistance of 600 N, and an acceleration of 

A) 6 m/s^2
B) 3 m/s^2
C) 500 m/s^2
D) 4 m/s^2
E) 10 m/s^2







Answer: D

A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about

A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about 

A) 1/2 N.
B) 1 N.
C) 5 N.
D) 7.5 N.
E) 10 N.








Answer: E

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction from the first force. The particle with both forces acting on it

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction from the first force. The particle with both forces acting on it 

A) is brought to a rapid halt.
B) decelerates gradually to a halt.
C) continues at the speed it had when it encountered the second force.
D) theoretically tends to accelerate toward the speed of light.
E) none of these








Answer: C

A 10-N block and a 1-N block lie on a horizontal frictionless table. To provide them with equal horizontal acceleration, we would have to push with

A 10-N block and a 1-N block lie on a horizontal frictionless table. To provide them with equal horizontal acceleration, we would have to push with 

A) equal forces on each block.
B) 10 times as much force on the heavier block.
C) 10 squared or 100 times as much force on the heavier block.
D) 1/10 as much force on the heavier block.
E) none of these

Answer: B

A bag of groceries has a mass of 10 kilograms and a weight of

A bag of groceries has a mass of 10 kilograms and a weight of 

A) about 1 N.
B) about 10 N.
C) about 100 N.
D) about 1000 N.
E) more than 1000 N.







Answer: C

A bag of groceries has a mass of 10 kilograms and a weight of

A bag of groceries has a mass of 10 kilograms and a weight of 

A) about 1 N.
B) about 10 N.
C) about 100 N.
D) about 1000 N.
E) more than 1000 N.






Answer: C

A car has a mass of 1000 kg and accelerates at 2 meters per second per second. What is the magnitude of the net force exerted on the car?

A car has a mass of 1000 kg and accelerates at 2 meters per second per second. What is the magnitude of the net force exerted on the car? 

A) 500 N
B) 1000 N
C) 1500 N
D) 2000 N
E) none of these







Answer: D

A heavy block at rest is suspended by a vertical rope. When the block is accelerated upward by the rope, the rope tension

A heavy block at rest is suspended by a vertical rope. When the block is accelerated upward by the rope, the rope tension 

A) increases.
B) decreases.
C) remains the same.






Answer: A

Which has zero acceleration? An object

Which has zero acceleration? An object 

A) at rest.
B) moving at constant velocity.
C) in mechanical equilibrium.
D) all of these
E) none of these






Answer: D

An apple weighs 1 N. When held at rest above your head, the net force on the apple is

An apple weighs 1 N. When held at rest above your head, the net force on the apple is 

A) 0 N.
B) 0.1 N.
C) 1 N.
D) 9.8 N.
E) none of these





Answer: A

An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is

An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is 

A) 0 N.
B) 5 N.
C) 25 N.
D) 150 N.







Answer: B

If an object's mass is decreasing while a constant force is applied to the object, the acceleration

If an object's mass is decreasing while a constant force is applied to the object, the acceleration 

A) decreases.
B) increases.
C) remains the same.








Answer: B

A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is

A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is 

A) the same as the force on the 1-kg book.
B) 10 times as much.
C) one-tenth as much.
D) zero.







Answer: B

A force is a vector quantity because it has both

A force is a vector quantity because it has both 

A) magnitude and direction.
B) mass and acceleration.
C) action and reaction counterparts.






Answer: A

An object's weight may properly be expressed in units of

An object's weight may properly be expressed in units of 

A) meters.
B) kilograms.
C) newtons.
D) cubic centimeters.








Answer: C

Compared to the mass of a certain object on Earth, the mass of the same object on the moon is

Compared to the mass of a certain object on Earth, the mass of the same object on the moon is 

A) one sixth as much.
B) the same.
C) six times as much.
D) zero.







Answer: B

Your weight is

Your weight is 

A) equal to your mass.
B) the gravitational attraction force between you and the Earth.
C) a property of mechanical equilibrium.
D) all of these

Answer: B

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same 

A) mass.
B) volume.
C) weight.
D) all of these
E) none of these









Answer: E

A kilogram is a measure of an object's

A kilogram is a measure of an object's 

A) weight
B) size
C) force
D) mass








Answer: D

Distance is to displacement as

Distance is to displacement as 

A) speed is to velocity
B) impulse is to momentum
C) force is to weight
D) velocity is to acceleration
E) none of the above choices are correct








Answer: A

A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun, straight down towards the water. Neglecting air resistance, the acceleration just before striking the water

A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun, straight down towards the water. Neglecting air resistance, the acceleration just before striking the water 

A) is greater for the dropped bullet.
B) is greater for the fired bullet.
C) is the same for each bullet.
D) depends on how high they started.
E) none of these








Answer: C

A car accelerates from rest for 5 seconds until it reaches a speed of 20 m/s. What is the car's acceleration in meters per second per second?

A car accelerates from rest for 5 seconds until it reaches a speed of 20 m/s. What is the car's acceleration in meters per second per second? 

A) 1
B) 2
C) 3
D) 4
E) 5







Answer: D

When a rock thrown straight upwards gets to the exact top of its path, its

When a rock thrown straight upwards gets to the exact top of its path, its 

A) velocity is zero and its acceleration is zero.
B) velocity is zero and its acceleration is about 10 meters per second per second.
C) velocity is about 10 m/s and its acceleration is zero.
D) velocity is about 10 m/s and its acceleration is about 10 meters per second per second.
E) none of these

Answer: B

If a projectile is fired straight up at a speed of 10 m/s, the time it takes to reach the top of its path is about

If a projectile is fired straight up at a speed of 10 m/s, the time it takes to reach the top of its path is about 

A) 1 second.
B) 2 seconds.
C) 10 seconds.
D) not enough information to estimate








Answer: A

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft?

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? 

A) about 60 m
B) about 120 m
C) about 180 m
D) more than 200 m








Answer: C

At one instant an object in free fall is moving downward at 50 meters per second. One second later its speed should be about

At one instant an object in free fall is moving downward at 50 meters per second. One second later its speed should be about 

A) 25 m/s.
B) 50 m/s.
C) 55 m/s.
D) 60 m/s.
E) 100 m/s.









Answer: D

A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about

A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about 

A) half as much.
B) the same.
C) twice as much.
D) four times as much.






Answer: B

If a car accelerates from rest at 2 meters per second per second, its speed 3 seconds later will be about

If a car accelerates from rest at 2 meters per second per second, its speed 3 seconds later will be about 

A) 2 m/s.
B) 3 m/s.
C) 4 m/s.
D) 6 m/s.







Answer: D

If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be

If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be 

A) constant.
B) less and less each second.
C) greater than the second before.
D) doubled.









Answer: C

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is 

A) zero.
B) equal to its weight divided by its mass.
C) equal to the product of its mass times its weight.







Answer: A

While an object near the Earth's surface is in free fall, its

While an object near the Earth's surface is in free fall, its 

A) velocity increases.
B) acceleration increases.
C) mass increases.
D) mass decreases.








Answer: A

A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval its acceleration is

A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval its acceleration is 

A) zero.
B) 10 km/hr.
C) 110 km/hr.
D) 1000 km/hr.








Answer: A

An airplane flies at 100km/h in still air. If it flies into a 10 km/h headwind, its groundspeed is

An airplane flies at 100km/h in still air. If it flies into a 10 km/h headwind, its groundspeed is 

A) 100 km/h
B) 110 km/h
C) 120 km/h
D) 90 KM/h








Answer: D

Which of the following is not a vector quantity?

Which of the following is not a vector quantity? 

A) Speed
B) velocity
C) acceleration
D) all are vector quantities







Answer: A

If no external forces are acting on a moving object, it will

If no external forces are acting on a moving object, it will 

A) continue moving at the same speed.
B) continue moving at the same velocity.
C) move slower and slower until it finally stops.








Answer: B

According to Newton's law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains

According to Newton's law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains 

A) move too slowly.
B) are much too heavy.
C) must go up and down hills.
D) always have forces that oppose their motion.

Answer: D

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to 

A) continue to follow a circular path.
B) follow a straight-line path.
C) increase its speed.
D) revolve in a smaller circle.





Answer: B

If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is

If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is 

A) inertia.
B) gravity.
C) acceleration.
D) resistance.







Answer: A

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor 

A) exactly below the midpoint of the ceiling.
B) ahead of the midpoint of the ceiling.
C) behind the midpoint of the ceiling.
D) More information is needed to solve this problem.
E) none of these

Answer: A