# GCU PHY102 week 1 Motion Exercises

GCU PHY102 week 1 Motion Exercises

Complete the following exercises.

1. Jane is collecting data for a ball rolling down a hill.
She measures out a set of different distances and then proceeds to use a
stopwatch to find the time it takes the ball to roll each distance.

a. What is the independent variable in her experiment?

b. What is the dependent variable in her experiment?

c. Give one control variable for her experiment.

2. Consider an experiment where you drop an object.

a. Briefly describe your proposed experiment. (Make sure it is controlled).

b. What would be the independent variable for your experiment?

c. What would be the dependent variable for your experiment?

d. Give one control variable for your experiment.

Consider a freely falling object. V = a * t

e. What is the acceleration (in m/s2) after 5 seconds of fall?

f. What is the acceleration (in m/s2) after 10 seconds of fall?

g. What is the velocity (in m/s) after 5 seconds of fall?

h. What is the velocity (in m/s) of 10 seconds of fall?3. A
sign is hung between two cables as illustrated below. If the sign weighs 350 N,
what is the te nsion (in N) in each cable?

4. A construction worker on a high-rise building is on a platform suspended between
two cables as illustrated below. The construction worker weighs 850 N, the
plank weighs 450 N, and the tension in the left cable is 550 N.

a. What is the tension (in N) in the right cable?

b. Explain

5. Two forces of 50 N and 30 N, respectively, are acting on an object. Find the net
force (in N) on the object if …

a. the forces are acting in the same direction

b. the forces are acting in opposite directions.

6. A box is pulled straight across the floor at a constant speed. It is pulled with a horizontal force of 48 N.

a. Find the
net force (in N) on the box.

7. Describe the speed and acceleration of the ball released from the top of the track shown
in the figure below.

8. Describe the speed and acceleration of the ball released from the top of the track shown
in the figure below.

9. You throw a ball upward with a speed of 14 m/s.
What is the acceleration of the ball after it leaves your hand? Ignore air resistance and provide an

10. How would your answer to the previous question change if you take into account the
effects of air resistance?

11. Describe the speed and acceleration of a person sky diving. Include in your explanation a description of
the motion before the parachute is opened as well as a description of the
motion after the parachute is opened.

12. A net force of 24 N is acting on a 4.0-kg object.
Find the acceleration in m/s2.

13. A person pulls horizontally with a force of 64 N on a 14-kg box. There is a force of friction between the box
and the floor of 36 N. Find the
acceleration of the box in m/s2. Show your work.

The remaining questions are multiple-choice questions:

14. One difference between a hypothesis and a theory is that a hypothesis

A. is a guess that has not been well tested, whereas a theory is a synthesis of
well-tested guesses.

B. is
testable, whereas a theory is not testable.

C. can be
revised, whereas a theory cannot be revised.

D. is not
testable, whereas a theory is testable.

15. A car
starts from rest and reached a speed of 24 m/s in 6 seconds. What is the acceleration of the car?

A. 144 m

B. 6 m/s2

C. 4 m/s2

D. 10 m/s2

E. 0 m/s2

16. Which of
the following forces is NOT a contact force?

A. Friction
force

B. Support
force

C. Force of
gravity

D. Tension
force

17. If you
pull horizontally on a desk with a force of 150 N and the desk doesn’t move,
the friction force must be 150 N. Now if you pull with 250 N so the desk slides
at constant velocity, the friction force is

A. more than
150 N, but less than 250 N.

B. 250 N.

C. more than
250.

18. Suppose a particle is accelerated through space by a constant 10 N force. Suddenly the
particles encounters a second force of 10 N in a direction opposite to that of
the first force. The particle

A. is brought to a rapid halt.

B. theoretically accelerates to speeds approaching the speed of light.

C. continues at the speed it had when it encountered the second force.

D. gradually slows down to a halt.

19. Newton’s First Law of Motion applies to

A. objects at rest only.

B. moving objects only.

C. both moving and nonmoving objects.

20. A freely falling object starts from rest. After falling for 2 seconds, it will have a

A. 5 m/s

B. 10 m/s

C. 20 m/s

D. 40 m/s

21. Suppose an object is in free fall. Each second the object falls

A. the same distance as in the second before.

B. a larger distance than in the second before.

C. with the same instantaneous speed.

D. with the same average speed.

GCU PHY102 week 1 Motion Exercises.