# Practice Test: Forces And Motion

20 Questions | Total Attempts: 2906  Settings  Sample test preparation for Forces and Motion unit.

• 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.
Your "weight" is properly defined as
• 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.
Which of the following graphs best represents the relationship between the gravitational force, F, that Earth exerts and the mass, m, of an object sitting at Earth's surface, that the force is exerted upon?
• 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

Related Topics Back to top