# Practice Test: Forces And Motion

20 Questions | Total Attempts: 1429  Settings  Sample test preparation for Forces and Motion unit.

Related Topics
• 1.
The free-body diagram below represents a 2000-kg elevator. What is the motion of the elevator if the tension in the cable is 1.96 ´ 104 N? (Assume 3 significant digits.)
• A.

The elevator might be accelerating upward.

• B.

The elevator might be accelerating downward.

• C.

The elevator must be at rest.

• D.

The elevator cannot be undergoing uniform motion.

• E.

The elevator must not be accelerating.

• 2.
• A.

The amount of material of which you are composed

• B.

The gravitational force which Earth exerts on you

• C.

The gravitational force you exert on Earth

• D.

The force you exert on a set of bathroom scales

• E.

None of the above

• 3.
The value of "g" at the surface of Mars is 3.7 N/kg. How much would a 60.0-kg person weigh at an altitude above the Martian surface equivalent to the planet's radius?
• A.

2.2 x 102 N

• B.

1.6 x 102 N

• C.

1.1 x 102 N

• D.

56 N

• E.

28 N

• 4.
• A.

A

• B.

B

• C.

C

• D.

D

• E.

E

• 5.
The gravitational field strength of Earth
• A.

Has a value of exactgly 9.8 N/kg [down] at all locations on its surface

• B.

Is greater at the equator than at the poles

• C.

Is smallest at the peak of Mount Everest, the highest elevation

• D.

Is largest at the deepest spot on the ocean floor

• E.

Is largest at the poles

• 6.
If you weighed 112 N on the Moon where g = 1.6 N/kg, how much would you weigh on Earth?
• A.

1.1 x 102 N

• B.

1.7 x 104 N

• C.

6.9 x 102 N

• D.

1.1 x 104 N

• E.

6.9 x 103 N

• 7.
According to Newton's law of universal gravitation, the gravitational force of attraction between two objects would be
• A.

Half as strong if they're moved twice as far apart

• B.

Twice as strong if they're moved half as far apart

• C.

Four times as strong if they're moved twice as far apart

• D.

Four times as strong if they're moved half as far apart

• E.

Twice as strong if they're moved twice as far apart

• 8.
What would the gravitational field strength be on a planet with half Earth's mass and half its radius?
• A.

78.4 N/kg

• B.

39.2 N/kg

• C.

19.6 N/kg

• D.

9.8 N/kg

• E.

4.9 N/kg

• 9.
Consider two planets, A and B. Planet A has half the mass and half the radius of planet B. The ratio of gA : gB would be
• A.

2 : 1

• B.

1 : 2

• C.

4 : 1

• D.

1 : 4

• E.

1 : 1

• 10.
Study the force system diagram pictured below and select the factor which would NOT influence the amount of kinetic friction.
• A.

Object's mass

• B.

Coefficient of kinetic friction

• C.

Normal force

• D.

Applied force

• E.

Gravitational field strength

• 11.
The coefficient of friction stems from the
• A.

Nature of the two surfaces in contact

• B.

Mass of the object

• C.

Strength of the applied force

• D.

Strength of the normal force

• E.

Strength of the gravitational force

• 12.
If the strength of the frictional force is equal to the applied force and oppositely directed, and assuming that all other forces may be ignored, the object
• A.

Must be at rest

• B.

Must be just about to move

• C.

May be at rest or moving at uniform velocity

• D.

Must be accelerating

• E.

Must be slowing down

• 13.
A chalk brush sits on a metre stick as pictured in the diagram. As one end of the metre stick is elevated, the chalk brush eventually begins to slide. Why?
• A.

The coefficient of friction changes.

• B.

The gravitational force on the brush changes.

• C.

The normal force on the brush changes.

• D.

The gravitational force begins to act along the metre stick.

• E.

An applied force is created.

• 14.
A 425-g model rocket is accelerated upward at 86 m/s2 by its engine. What is the value of the force exerted by the engine on the rocket?
• A.

41 N [up]

• B.

41 N [down]

• C.

37 N [up]

• D.

32 N [up]

• E.

32 N [down]

• 15.
A 4.0-kg object, A, and a 2.0-kg object, B, are connected with a rope. A force is applied to another rope attached to the 2.0-kg object that pulls both A and B along a horizontal surface. Which of the following statements is true?
• A.

The force that B exerts on A is greater than the force that A exerts on B.

• B.

The force that A exerts on B is greater than the force that B exerts on A.

• C.

The force that B exerts on A is equal to the force that A exerts on B provided that the system slides with uniform motion.

• D.

The force that B exerts on A is equal to the force that A exerts on B regardless of the motion of the system.

• E.

The sum of the applied force and the force that B exerts on A is equal to the force that A exerts on B.

• 16.
A 1.5-kg cart is pulled with a force of 7.3 N at an angle of 40° above the horizontal. If a kinetic friction force of 3.2 N acts against the motion, the cart’s acceleration along the horizontal surface will be
• A.

1.0 m/s2

• B.

1.6 m/s2

• C.

2.4 m/s2

• D.

2.7 m/s2

• E.

5.0 m/s2

• 17.
A 1.8-kg object is pulled along the floor with a force of 7.0 N acting horizontally. If the object accelerates at 2.4 m/s2, how much kinetic friction is acting?
• A.

30 N

• B.

11 N

• C.

8.3 N

• D.

7.8 N

• E.

2.7 N

• 18.
Which of the following statements concerning friction is true?
• A.

The frictional force always acts oppositely to the applied force.

• B.

For two given surfaces, the coefficient of static friction is generally greater than the coefficient of kinetic friction.

• C.

Friction is a force which is unavoidable and serves no practical purpose.

• D.

Two very highly-polished surfaces in contact with one another will have very little friction between them.

• E.

Friction always acts in the direction of motion.

• 19.
If all other forces can be ignored and the strength of the frictional force is greater than the applied force and oppositely directed, the object
• A.

Could be speeding up or slowing down

• B.

Must be speeding up

• C.

Must be slowing down

• D.

Could be moving with uniform motion

• E.

Could be stopped

• 20.
The free-body diagram of a block being pushed up a rough ramp is best represented by
• A.

A

• B.

B

• C.

C

• D.

D

• E.

E