1. In this lab, the force pulling the weight was supplied by gravity. Why wasn't the acceleration of the weight always 9.8 m/s²? Pendulum Motion

This lab will be completed using the Pendulum Lab. Click on the Lab button on the bottom of the screen to go to the correct page to begin.

Experiment 1: Increasing the Hanging Mass

Make sure the button on the bottom showing only one weight is on.

Fill out the following table and use the lab to visualize the path of the weight on the pendulum.Let mrepresent the mass of the weight, represent the angle of the arc created with one full swing of the pendulum, Lrepresent the length of the cable (also the radius of the circle), arepresent the linear acceleration, and represent the angular acceleration.

a = -gsin

= a/L

m (kg)		L (m)	a(m/s2)	(rad/s2)
0.10	100	0.70
0.70	100	0.70
1.10	100	0.70

Experiment 2: Increasing Distance and Angle

Fill out the following table.Let mrepresent the mass of the weight, represent the angle of the arc created with one full swing of the pendulum, Lrepresent the length of the cable (also the radius of the circle),arepresent the linear acceleration, represent the angular acceleration, and T represent the period time. To obtain the period for each trial click Period Timer on the bottom right.

m (kg)		L (m)	a(m/s2)	(rad/s2)	T (s)
0.70	100	0.30
0.70	100	0.70
0.70	100	1.00

m (kg)		L (m)	a(m/s2)	(rad/s2)	T (s)
0.70	20	0.70
0.70	40	0.70
0.70	60	0.70

1. In this lab, the force pulling the weight was supplied by gravity. Why wasn't the acceleration of the weight always 9.8 m/s²?
2. If there were friction in the air, how would you expect this to affect your measured value of the acceleration? Explain your reasoning.
3. What happened to the acceleration as the hanging mass was increased?
4. For the experiments in which the hanging mass was kept constant and the length changed, what happened to the radial acceleration as you increased the length of the pendulum?
5. How did the period time change as the length of the pendulum increased? How does this relate to the motion of planets in orbit around the Sun? Explain your answer.
6. Based on your results from Experiment 2, what can you say about the relationship between the period and the angle? Explain your reasoning.

https://phet.colorado.edu/sims/html/pendulum-lab/latest/pendulum-lab_en.html