Question 1

You throw a ball up in the air and hold your hand under it to catch it when it comes down. The reason why the ball stops is because

Accepted Answer

A)  your hand is there: your hand exerts no force on the ball. 
B)  your hand exerts a force on the ball perpendicular to its velocity. 
C)  your hand exerts a force on the ball in the direction of its velocity. 
D)  your hand exerts a force on the ball in the direction opposite to its velocity. 
E)  your hand and the ball exert forces in the same direction on each other. 
A)  your hand is there: your hand exerts no force on the ball. 
B)  your hand exerts a force on the ball perpendicular to its velocity. 
C)  your hand exerts a force on the ball in the direction of its velocity. 
D)  your hand exerts a force on the ball in the direction opposite to its velocity. 
E)  your hand and the ball exert forces in the same direction on each other. D

Question 2

The total force needed to drag a box at constant speed across a surface with coefficient of kinetic friction μk is least when the force is applied at an angle θ such that

Accepted Answer

A)  sinθ = μk. 
B)  cosθ = μk. 
C)  tanθ = μk. 
D)  cotθ = μk. 
E)  secθ = μk. 
A)  sinθ = μk. 
B)  cosθ = μk. 
C)  tanθ = μk. 
D)  cotθ = μk. 
E)  secθ = μk. C

Question 3

Two blocks are accelerated across a horizontal frictionless surface as shown. Frictional forces keep the two blocks from sliding relative to each other, and the two move with the same acceleration. If F = 1.2 N and M = 1.0 kg, what is the horizontal component (frictional force) of the force of the small block on the large block?

Accepted Answer

A)  0.48 N to the right 
B)  0.72 N to the right 
C)  0.72 N to the left 
D)  0.48 N to the left 
E)  0.65 N to the left 
A)  0.48 N to the right 
B)  0.72 N to the right 
C)  0.72 N to the left 
D)  0.48 N to the left 
E)  0.65 N to the left B

Question 4

The coefficient of kinetic friction between the surface and the larger block is 0.25, and the coefficient of kinetic friction between the surface and the smaller block is 0.40. If F = 22N and M = 1.0 kg in the figure, what is the magnitude of the acceleration of either block?

Accepted Answer

A)  1.8 m/s2 
B)  2.6 m/s2 
C)  1.4 m/s2 
D)  2.2 m/s2 
E)  3.7 m/s2 
A)  1.8 m/s2 
B)  2.6 m/s2 
C)  1.4 m/s2 
D)  2.2 m/s2 
E)  3.7 m/s2

Question 5

A 3.0-kg block slides on a frictionless 20° inclined plane. A force of 16 N acting parallel to the incline and up the incline is applied to the block. What is the acceleration of the block?

Accepted Answer

A)  2.0 m/s2 down the incline 
B)  5.3 m/s2 up the incline 
C)  2.0 m/s2 up the incline 
D)  3.9 m/s2 down the incline 
E)  3.9 m/s2 up the incline 
A)  2.0 m/s2 down the incline 
B)  5.3 m/s2 up the incline 
C)  2.0 m/s2 up the incline 
D)  3.9 m/s2 down the incline 
E)  3.9 m/s2 up the incline

Question 6

You hold a tennis racket in your hand. On top of the racket you have balanced a ball. Which statement is true?

Accepted Answer

A)  The force of your hand on the racket and the force of the ball on the racket are equal and opposite. 
B)  The force of the racket on your hand and the force of the ball on the racket are equal and opposite. 
C)  The force of your hand on the racket and the force of the racket on the ball are equal and opposite. 
D)  The force of the racket on your hand and the force of the racket on the ball are equal and opposite. 
E)  The force of your hand on the racket and the force of the racket on your hand are equal and opposite. 
A)  The force of your hand on the racket and the force of the ball on the racket are equal and opposite. 
B)  The force of the racket on your hand and the force of the ball on the racket are equal and opposite. 
C)  The force of your hand on the racket and the force of the racket on the ball are equal and opposite. 
D)  The force of the racket on your hand and the force of the racket on the ball are equal and opposite. 
E)  The force of your hand on the racket and the force of the racket on your hand are equal and opposite.

Question 7

A box is dropped onto a conveyor belt moving at 2 m/s. If the coefficient of friction between the box and the belt is 0.3, how long before the box moves without slipping?

Accepted Answer

The answer of A box is dropped onto a conveyor...

Question 8

A person weighing 0.70 kN rides in an elevator that has an upward acceleration of 1.5 m/s2. What is the magnitude of the force of the elevator floor on the person?

Accepted Answer

A)  0.11 kN 
B)  0.81 kN 
C)  0.70 kN 
D)  0.59 kN 
E)  0.64 kN 
A)  0.11 kN 
B)  0.81 kN 
C)  0.70 kN 
D)  0.59 kN 
E)  0.64 kN

Question 9

Which of the following is not a fundamental force?

Accepted Answer

A)  the gravitational force 
B)  the electromagnetic force 
C)  the strong force 
D)  the force of forward motion also known as the inertial force 
E)  Choose this answer if two of the named forces are not fundamental. 
A)  the gravitational force 
B)  the electromagnetic force 
C)  the strong force 
D)  the force of forward motion also known as the inertial force 
E)  Choose this answer if two of the named forces are not fundamental.

Question 10

Two forces are the only forces acting on a 3.0-kg object which moves with an acceleration of 3.0 m/s2 in the positive y direction. If one of the forces acts in the positive x direction and has a magnitude of 8.0 N, what is the magnitude of the other force?

Accepted Answer

A)  12 N 
B)  14 N 
C)  16 N 
D)  18 N 
E)  22 N 
A)  12 N 
B)  14 N 
C)  16 N 
D)  18 N 
E)  22 N

Question 11

The horizontal surface on which the objects slide is frictionless. If F = 6.0 N and M = 1.0 kg, what is the magnitude of the force exerted on the large block by the small block?

Accepted Answer

A)  7.7 N 
B)  9.8 N 
C)  9.1 N 
D)  8.4 N 
E)  6.5 N 
A)  7.7 N 
B)  9.8 N 
C)  9.1 N 
D)  8.4 N 
E)  6.5 N

Question 12

If M = 2.0 kg, what is the tension in string 1?

Accepted Answer

A)  1.2 N 
B)  11 N 
C)  34 N 
D)  3.5 N 
E)  40 N 
A)  1.2 N 
B)  11 N 
C)  34 N 
D)  3.5 N 
E)  40 N

Question 13

A 1.5-kg object has a velocity of 5   m/s at t = 0. It is accelerated at a constant rate for five seconds after which it has a velocity of (6   + 12   ) m/s. What is the direction of the resultant force acting on the object during this time interval?

Accepted Answer

A)  65° 
B)  56° 
C)  61° 
D)  49° 
E)  27° 
A)  65° 
B)  56° 
C)  61° 
D)  49° 
E)  27°

Question 14

An object on the flat bed of a truck that is accelerating along a straight horizontal road. The coefficient of static friction is 0.300 in this case. Of the following choices, which is the lowest value of acceleration that would result in the object sliding on the bed of the truck?

Accepted Answer

A)  0.280 m/s2 
B)  0.310 m/s2 
C)  2.93 m/s2 
D)  2.99 m/s2 
E)  3.02 m/s2 
A)  0.280 m/s2 
B)  0.310 m/s2 
C)  2.93 m/s2 
D)  2.99 m/s2 
E)  3.02 m/s2

Question 15

Exhibit 5-2
A 4.00 kg block is suspended from the roof of an elevator. A 2.00 kg block is suspended from the 4.00 kg block. The tensions in strings 1 and 2 are labeled   and   .   Use this exhibit to answer the following question(s).
-Refer to Exhibit 5-2. When the elevator accelerates upwards with an acceleration of 2.20 m/s2, the magnitudes of   and   are

Accepted Answer

A)  30.4 N; 15.2 N. 
B)  39.2 N; 19.6 N. 
C)  45.6 N; 15.2 N. 
D)  48.0 N; 24.0 N. 
E)  72.0 N; 24.0 N. 
A)  30.4 N; 15.2 N. 
B)  39.2 N; 19.6 N. 
C)  45.6 N; 15.2 N. 
D)  48.0 N; 24.0 N. 
E)  72.0 N; 24.0 N.

Question 16

In order to jump off the floor, the floor must exert a force on you

Accepted Answer

A)  in the direction of and equal to your weight. 
B)  opposite to and equal to your weight. 
C)  in the direction of and less than your weight. 
D)  opposite to and less than your weight. 
E)  opposite to and greater than your weight. 
A)  in the direction of and equal to your weight. 
B)  opposite to and equal to your weight. 
C)  in the direction of and less than your weight. 
D)  opposite to and less than your weight. 
E)  opposite to and greater than your weight.

Question 17

The system shown is released from rest and moves 50 cm in 1.0 s. What is the value of M? All surfaces are frictionless.

Accepted Answer

A)  0.42 kg 
B)  0.34 kg 
C)  0.50 kg 
D)  0.59 kg 
E)  0.68 kg 
A)  0.42 kg 
B)  0.34 kg 
C)  0.50 kg 
D)  0.59 kg 
E)  0.68 kg

Question 18

The frictional force of the floor on a large suitcase is least when the suitcase is

Accepted Answer

A)  pushed by a force parallel to the floor. 
B)  dragged by a force parallel to the floor. 
C)  pulled by a force directed at an angle θ above the floor. 
D)  pushed by a force directed at an angle θ into the floor. 
E)  turned on its side and pushed by a force parallel to the floor. 
A)  pushed by a force parallel to the floor. 
B)  dragged by a force parallel to the floor. 
C)  pulled by a force directed at an angle θ above the floor. 
D)  pushed by a force directed at an angle θ into the floor. 
E)  turned on its side and pushed by a force parallel to the floor.

Question 19

Given the equation   , which answer provides the best description of a possible physical situation?

Accepted Answer

A)  A 3.00 kg mass is suspended from the ceiling. 
B)  A 2.00 kg mass hanging over a pulley drags a 3.00 kg mass along a frictionless horizontal surface. 
C)  A 3.00 kg mass hanging over a pulley drags a 2.00 kg mass along a frictionless horizontal surface. 
D)  A 3.00 kg mass hanging over a pulley drags a 5.00 kg mass along a frictionless horizontal surface. 
E)  A 5.00 kg mass hanging over a pulley drags a 3.00 kg mass along a frictionless horizontal surface. 
A)  A 3.00 kg mass is suspended from the ceiling. 
B)  A 2.00 kg mass hanging over a pulley drags a 3.00 kg mass along a frictionless horizontal surface. 
C)  A 3.00 kg mass hanging over a pulley drags a 2.00 kg mass along a frictionless horizontal surface. 
D)  A 3.00 kg mass hanging over a pulley drags a 5.00 kg mass along a frictionless horizontal surface. 
E)  A 5.00 kg mass hanging over a pulley drags a 3.00 kg mass along a frictionless horizontal surface.

Question 20

An astronaut who weighs 800 N on the surface of the earth lifts off from planet Zuton in a space ship. The free-fall acceleration on Zuton is 3.0 m/s2 (down). At the moment of liftoff the acceleration of the space ship is 0.50 m/s2 (up). What is the magnitude of the force of the space ship on the astronaut?

Accepted Answer

A)  41 N 
B)  0.29 kN 
C)  0.24 kN 
D)  0.20 kN 
E)  0.37 kN 
A)  41 N 
B)  0.29 kN 
C)  0.24 kN 
D)  0.20 kN 
E)  0.37 kN

Exam 5: The Laws of Motion

You throw a ball up in the air and hold your hand under it to catch it when it comes down. The reason why the ball stops is because

The total force needed to drag a box at constant speed across a surface with coefficient of kinetic friction μk is least when the force is applied at an angle θ such that

The coefficient of kinetic friction between the surface and the larger block is 0.25, and the coefficient of kinetic friction between the surface and the smaller block is 0.40. If F = 22N and M = 1.0 kg in the figure, what is the magnitude of the acceleration of either block?

A 3.0-kg block slides on a frictionless 20° inclined plane. A force of 16 N acting parallel to the incline and up the incline is applied to the block. What is the acceleration of the block?

You hold a tennis racket in your hand. On top of the racket you have balanced a ball. Which statement is true?

A box is dropped onto a conveyor belt moving at 2 m/s. If the coefficient of friction between the box and the belt is 0.3, how long before the box moves without slipping?

A person weighing 0.70 kN rides in an elevator that has an upward acceleration of 1.5 m/s2. What is the magnitude of the force of the elevator floor on the person?

Which of the following is not a fundamental force?

Two forces are the only forces acting on a 3.0-kg object which moves with an acceleration of 3.0 m/s2 in the positive y direction. If one of the forces acts in the positive x direction and has a magnitude of 8.0 N, what is the magnitude of the other force?

The horizontal surface on which the objects slide is frictionless. If F = 6.0 N and M = 1.0 kg, what is the magnitude of the force exerted on the large block by the small block?

If M = 2.0 kg, what is the tension in string 1?

A 1.5-kg object has a velocity of 5 m/s at t = 0. It is accelerated at a constant rate for five seconds after which it has a velocity of (6 + 12 ) m/s. What is the direction of the resultant force acting on the object during this time interval?

An object on the flat bed of a truck that is accelerating along a straight horizontal road. The coefficient of static friction is 0.300 in this case. Of the following choices, which is the lowest value of acceleration that would result in the object sliding on the bed of the truck?

In order to jump off the floor, the floor must exert a force on you

The system shown is released from rest and moves 50 cm in 1.0 s. What is the value of M? All surfaces are frictionless.

The frictional force of the floor on a large suitcase is least when the suitcase is

Given the equation , which answer provides the best description of a possible physical situation?

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The total force needed to drag a box at constant speed across a surface with coefficient of kinetic friction μ_k is least when the force is applied at an angle θ such that

A person weighing 0.70 kN rides in an elevator that has an upward acceleration of 1.5 m/s². What is the magnitude of the force of the elevator floor on the person?

Two forces are the only forces acting on a 3.0-kg object which moves with an acceleration of 3.0 m/s² in the positive y direction. If one of the forces acts in the positive x direction and has a magnitude of 8.0 N, what is the magnitude of the other force?