PHY-102: 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?
The independent variable is the ball.
b. What is the dependent variable in her experiment?
The stopwatch is the dependent variable.
c. Give one control variable for her experiment.
The distance is the control variable.
2. Consider an experiment where you drop an object.
a. Briefly describe your proposed experiment. (Make sure it is controlled).
For my experiment, I will drop my phone off a 10ft ledge at different heights.
b. What would be the independent variable for your experiment?
The independent variable is my phone.
c. What would be the dependent variable for your experiment?
The distance of the 10ft ledge is dependent for this experiment.
d. Give one control variable for your experiment.
The overall heights in which I chose in conducting my experiment.
Consider a freely falling object. V = a * t
e. What is the acceleration (in m/s2) after 5 seconds of fall?
5 seconds = 9.8 m/s2
f. What is the acceleration (in m/s2) after 10 seconds of fall?
10 seconds = 9.8 m/s2
g. What is the velocity (in m/s) after 5 seconds of fall?
49 m/s
h. What is the velocity (in m/s) of 10 seconds of fall?
98 m/s
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?
T = 750 N
b. Explain your answer.
-FNet = Ma = 0
-550 – 450 – 850 + T = 0
T = 750 N
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
30 + 50 = 80N
b. the forces are acting in opposite directions.
50 - 30= 20N
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.
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?
The independent variable is the ball.
b. What is the dependent variable in her experiment?
The stopwatch is the dependent variable.
c. Give one control variable for her experiment.
The distance is the control variable.
2. Consider an experiment where you drop an object.
a. Briefly describe your proposed experiment. (Make sure it is controlled).
For my experiment, I will drop my phone off a 10ft ledge at different heights.
b. What would be the independent variable for your experiment?
The independent variable is my phone.
c. What would be the dependent variable for your experiment?
The distance of the 10ft ledge is dependent for this experiment.
d. Give one control variable for your experiment.
The overall heights in which I chose in conducting my experiment.
Consider a freely falling object. V = a * t
e. What is the acceleration (in m/s2) after 5 seconds of fall?
5 seconds = 9.8 m/s2
f. What is the acceleration (in m/s2) after 10 seconds of fall?
10 seconds = 9.8 m/s2
g. What is the velocity (in m/s) after 5 seconds of fall?
49 m/s
h. What is the velocity (in m/s) of 10 seconds of fall?
98 m/s
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?
T = 750 N
b. Explain your answer.
-FNet = Ma = 0
-550 – 450 – 850 + T = 0
T = 750 N
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
30 + 50 = 80N
b. the forces are acting in opposite directions.
50 - 30= 20N
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.
