Question 1

When a 40-N force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30 °\degree°  above the horizontal, the acceleration of the crate is 2.0 m/s2, up the incline. The mass of the crate is:

Accepted Answer

A)   3.8 kg
B)   4.1 kg
C)   5.8 kg
D)   6.2 kg
E)   10 kg

Question 2

A car travels east at constant velocity. The net force on the car is:

Accepted Answer

A)   east
B)   west
C)   up
D)   down
E)   zero E

Question 3

An object moving at constant velocity in an inertial frame must:

Accepted Answer

A)   have a net force on it
B)   eventually stop due to gravity
C)   not have any force of gravity acting on it
D)   have zero net force acting on it
E)   have no frictional force acting on it

Question 4

A 90-kg man stands in an elevator that has a downward acceleration of 1.4 m/s2. The force exerted by him on the floor is about:

Accepted Answer

A)   zero
B)   90 N
C)   760 N
D)   880 N
E)   1010 N

Question 5

A 90-kg man stands in an elevator that is moving up at a constant speed of 5.0 m/s. The force exerted by him on the floor is about:

Accepted Answer

A)   zero
B)   90 N
C)   880 N
D)   450 N
E)   49 N

Question 6

A heavy steel ball B is suspended by a cord from a block of wood W. The entire system is dropped through the air. Neglecting air resistance, the tension in the cord is:

Accepted Answer

A)   zero
B)   the difference in the masses of B and W
C)   the difference in the weights of B and W
D)   the weight of B
E)   none of these

Question 7

Two blocks with masses m and M are pushed along a horizontal frictionless surface by a horizontal applied force  as shown. The magnitude of the force of either of these blocks on the other is:

Accepted Answer

A)   mF/(m + M) 
B)   mF/M
C)   mF/(M - m) 
D)   MF/(M + m) 
E)   MF/m A

Question 8

A newton is the force:

Accepted Answer

A)   of gravity on a 1 kg body
B)   of gravity on a 1 g body
C)   that gives a l g body an acceleration of 1 cm/s2
D)   that gives a 1 kg body an acceleration of 1 m/s2
E)   that gives a 1 kg body an acceleration of 9.8 m/s2

Question 9

A force of 1 N is:

Accepted Answer

A)   1 kg/s
B)   1kg .m/s
C)   1kg .m/s2
D)   1kg .m2/s
E)   1kg .m2/s2

Question 10

A crate rests on a horizontal surface and a woman pulls on it with a 10-N force. Rank the situations shown below according to the magnitude of the normal force exerted by the surface on the crate, least to greatest.

Accepted Answer

A)   1, 2, 3
B)   2, 1, 3
C)   2, 3, 1
D)   1, 3, 2
E)   3, 2, 1

Question 11

A feather and a lead ball are dropped from rest in vacuum on the Moon. The acceleration of the feather is:

Accepted Answer

A)   more than that of the lead ball
B)   the same as that of the lead ball
C)   less than that of the lead ball
D)   9.8 m/s2
E)   zero since it floats in a vacuum

Question 12

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline. If the incline is 25 °\degree°  above the horizontal the magnitude of the normal force of the incline on the crate is:

Accepted Answer

A)   4.1 N
B)   4.6 N
C)   8.9 N
D)   11 N
E)   23 N

Question 13

A massless rope passes over a massless pulley suspended from the ceiling. A 4-kg block is attached to one end and a 5-kg block is attached to the other end. The acceleration of the 5-kg block is:

Accepted Answer

A)   g/4
B)   5g/9
C)   4g/9
D)   g/5
E)   g/9

Question 14

Equal forces  act on isolated bodies A and B. The mass of B is three times that of A. The magnitude of the acceleration of A is:

Accepted Answer

A)   three times that of B
B)   1/3 that of B
C)   the same as B
D)   nine times that of B
E)   1/9 that of B A

Question 15

Which of the following quantities is NOT a vector?

Accepted Answer

A)   Mass
B)   Displacement
C)   Weight
D)   Acceleration
E)   Force

Question 16

A car moves horizontally with a constant acceleration of 3 m/s2. A ball is suspended by a string from the ceiling of the car; the ball does not swing, being at rest with respect to the car. What angle does the string make with the vertical?

Accepted Answer

A)   17 °\degree° 
B)   35 °\degree° 
C)   52 °\degree° 
D)   73 °\degree° 
E)   Cannot be found without knowing the length of the string

Question 17

A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30 °\degree°  above the horizontal. The mass of the crate is:

Accepted Answer

A)   3.3 kg
B)   3.8 kg
C)   5.7 kg
D)   6.5 kg
E)   160 kg

Question 18

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline. If the incline is 25 °\degree°  above the horizontal the magnitude of the applied force is:

Accepted Answer

A)   4.1 N
B)   4.6 N
C)   8.9 N
D)   11 N
E)   23 N

Question 19

An object rests on a horizontal frictionless surface. A horizontal force of magnitude F is applied. This force produces an acceleration:

Accepted Answer

A)   only if F is larger than the weight of the object
B)   only while the object suddenly changes from rest to motion
C)   always
D)   only if the inertia of the object decreases
E)   only if F is increasing

Question 20

A 5-kg concrete block is lowered with a downward acceleration of 2.8 m/s2 by means of a rope. The force of the block on the Earth is:

Accepted Answer

A)   14 N, up
B)   14 N, down
C)   35 N, up
D)   35 N, down
E)   49 N, up

Exam 5: Force and Motion I

When a 40-N force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30 °\degree° above the horizontal, the acceleration of the crate is 2.0 m/s2, up the incline. The mass of the crate is:

Correct AnswerverifiedShow Answer

A car travels east at constant velocity. The net force on the car is:

Correct AnswerverifiedE

An object moving at constant velocity in an inertial frame must:

Correct AnswerverifiedShow Answer

A 90-kg man stands in an elevator that has a downward acceleration of 1.4 m/s2. The force exerted by him on the floor is about:

Correct AnswerverifiedShow Answer

A 90-kg man stands in an elevator that is moving up at a constant speed of 5.0 m/s. The force exerted by him on the floor is about:

Correct AnswerverifiedShow Answer

A heavy steel ball B is suspended by a cord from a block of wood W. The entire system is dropped through the air. Neglecting air resistance, the tension in the cord is:

Correct AnswerverifiedShow Answer

Two blocks with masses m and M are pushed along a horizontal frictionless surface by a horizontal applied force as shown. The magnitude of the force of either of these blocks on the other is:

Correct AnswerverifiedA

A newton is the force:

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A force of 1 N is:

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A crate rests on a horizontal surface and a woman pulls on it with a 10-N force. Rank the situations shown below according to the magnitude of the normal force exerted by the surface on the crate, least to greatest.

Correct AnswerverifiedShow Answer

A feather and a lead ball are dropped from rest in vacuum on the Moon. The acceleration of the feather is:

Correct AnswerverifiedShow Answer

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline. If the incline is 25 °\degree° above the horizontal the magnitude of the normal force of the incline on the crate is:

Correct AnswerverifiedShow Answer

A massless rope passes over a massless pulley suspended from the ceiling. A 4-kg block is attached to one end and a 5-kg block is attached to the other end. The acceleration of the 5-kg block is:

Correct AnswerverifiedShow Answer

Equal forces act on isolated bodies A and B. The mass of B is three times that of A. The magnitude of the acceleration of A is:

Correct AnswerverifiedA

Which of the following quantities is NOT a vector?

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A car moves horizontally with a constant acceleration of 3 m/s2. A ball is suspended by a string from the ceiling of the car; the ball does not swing, being at rest with respect to the car. What angle does the string make with the vertical?

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A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30 °\degree° above the horizontal. The mass of the crate is:

Correct AnswerverifiedShow Answer

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline. If the incline is 25 °\degree° above the horizontal the magnitude of the applied force is:

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An object rests on a horizontal frictionless surface. A horizontal force of magnitude F is applied. This force produces an acceleration:

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A 5-kg concrete block is lowered with a downward acceleration of 2.8 m/s2 by means of a rope. The force of the block on the Earth is:

Correct AnswerverifiedShow Answer

When a 40-N force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30 $\degree$ above the horizontal, the acceleration of the crate is 2.0 m/s², up the incline. The mass of the crate is:

Correct Answer
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E

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A 90-kg man stands in an elevator that has a downward acceleration of 1.4 m/s². The force exerted by him on the floor is about:

Correct Answer
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A

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A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline. If the incline is 25 $\degree$ above the horizontal the magnitude of the normal force of the incline on the crate is:

Correct Answer
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A

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A car moves horizontally with a constant acceleration of 3 m/s². A ball is suspended by a string from the ceiling of the car; the ball does not swing, being at rest with respect to the car. What angle does the string make with the vertical?

Correct Answer
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A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30 $\degree$ above the horizontal. The mass of the crate is:

Correct Answer
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A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline. If the incline is 25 $\degree$ above the horizontal the magnitude of the applied force is:

Correct Answer
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Correct Answer
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A 5-kg concrete block is lowered with a downward acceleration of 2.8 m/s² by means of a rope. The force of the block on the Earth is:

Correct Answer
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