# Pre-AP PHYSICS CHAPTER FOUR PRETEST

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```					          Pre-AP PHYSICS CHAPTER FOUR PRETEST
DEFINITIONS:

1. Parallel Forces
2. Resultant Forces
3. Equilibrant Forces
4. Friction
5. Equilibrium
6. Component Forces
7. coefficient of friction
8. Newton’s Laws
9. acceleration
10. free-body diagram
11. normal force

MULTIPLE CHOICE:

1. A body is NOT in equilibrium if: A) it is moving at constant speed in a straight line, B) there
is an unbalanced force acting on the body, C) it is at rest, D) its motion is unchanged.

2. Resolution of forces is the procedure for finding:   A) parallel forces, B) component forces,
C) equilibrant forces, D) resultant forces.

3. Friction is a disadvantage: A) in walking along a sidewalk, B) in automobile brakes, C) in
roller bearings on freight cars, D) between bike tires and the dirt trail.

4. Which of the following statements about friction is FALSE? Friction: A) involves objects that
are in physical contact, B) is less if surfaces are very smooth, C) is a force that resists motion,
D) is caused by uneven surfaces of touching objects.

5. A box is pulled along a level floor at constant speed by a rope that makes a 45 degree angle
with the floor. The box weighs 100 N. The coefficient of sliding friction is 0.75. The force
exerted on the rope is: A) 75 N, B) between 75 N and 100 N, C) 100 N, D) greater than 100
N.

6. What causes a moving object to change direction?
a. acceleration            b. velocity            c. inertia                d. force

7. Which of the following is the tendency of an object to maintain its state of motion?
a. acceleration                b. inertia            c. force                d. velocity

8. A wagon with a weight of 300.0 N is accelerated across a level surface at 0.5 m/s2. What net
force acts on the wagon?
a. 9.0 N                     b. 15 N               c. 150 N               d. 610 N

9. The statement by Newton that for every action there is an equal and opposite reaction is
which of his laws of motion?
a. first                     b. second          c. third                   d. fourth
10. The magnitude of the force of gravity acting on an object is:
a. frictional force          b. weight               c. inertia              d. mass

QUESTIONS:

1. Define equilibrium. What conditions are required for equilibrium?

2. On point 0, a force of 25.0 N acts eastward and a force of 10.0 N acts southward. Calculate
the magnitude and direction of the resultant force.

3. A carton weighing 250 N is resting on a ramp that makes an angle of 20.0 degrees with the
horizontal. What are the magnitudes of the components of the weight of the carton parallel to
the ramp and perpendicular to it?

4. If a steel block weighing 4.63 N can be pulled at a constant speed across a smooth steel
plate by a force of 2.64 N, what is the coefficient of sliding friction of steel on steel?

5. When a car is moving, what happens to the velocity and acceleration of the car if the air
resistance becomes equal to the force acting in the opposite direction?

6. In a game of tug-of-war, a rope is pulled to the left with a force of 75 N and to the right with a
force of 102 N. What is the magnitude and direction of the net external force on the rope?

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