PHY-102: Motion Exercises Review
Complete the following exercises.
1. Jane is collecting data for a ball rolling down a hill. She measures out a set
... [Show More] 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 ball
b. What is the dependent variable in her experiment? The stopwatch
c. Give one control variable for her experiment. The different distances
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 a coin off a 10ft porch at different heights.
b. What would be the independent variable for your experiment? The independent variable is the coin.
c. What would be the dependent variable for your experiment? The distance of the 10ft porch is dependent for this experiment.
d. Give one control variable for your experiment.
The heights in which I stand while conducting my experiment.
3. Consider a freely falling object.
a. What is the acceleration (in m/s2) after 5 seconds of fall? 9.8 m/s^2
b. What is the acceleration (in m/s2) after 10 seconds of fall? 9.8m/s^2
c. What is the velocity (in m/s) after 5 seconds of fall? 49m/s
d. What is the velocity (in m/s) of 10 seconds of fall? 98m/s
4. A sign is hung between two cables as illustrated below. If the sign weighs 350 N, what is the tension (in N) in each cable? The tension in each cable is 175N
T=mg/2=350/2=175N
5. 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 = 750N
b. Explain your answer. 850+450-550=750
6. 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: 80 N
b. the forces are acting in opposite directions: 20 N
7. 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. 48
b. Find the force of friction (in N) from the floor on the box. 0
c. The person pulling on the box stops pulling and the box comes to a rest. Find the force of friction (in N) on the box when at rest. -48
8. A bowling ball rolls 32 meters in 0.8 seconds. Find the average speed (in m/s) of the bowling ball in m/s. 32/.8 = 40
9. A car accelerates from 3.5 m/s to 17 m/s in 4.5 seconds. Find the acceleration of the car in m/s2. 3m/s^2
10. Rank the following from lowest to highest: C, A, B
a. The support force on you standing in an elevator at rest.
b. The support force on you standing in an elevator accelerating upward.
c. The support force on you standing in an elevator accelerating downward. [Show Less]