Cup-sling Lab: Circular Motion Discovery Activity Analysis I  A. Does a force have to be continually exerted by the elastic band to keep the cup-sling whirling at a constant speed? How did you know?

 B. When the cup-sling moved in a circle, it was changing direction all the time. What caused the cup-sling to change direction?  C. When the cup-sling moved in a circle at a constant speed, did it accelerate? Explain your answer.

 D. What happens to the length of the elastic band as the force needed to whirl the cup-sling in a horizontal circle increases?

 E. Along what path would the cup follow if the band were released while the cup was whirling?  F. Repeat the experiment. Record the time it takes to complete 10 horizontal circles and estimate the length of the radius using a meter stick. Record results and calculate the tangential speed of the cup using the formula on the board.

Analysis II  A. What happened to the total length of the elastic bands when you increased the mass in the cup?

 B. How did the increase in mass affect the force by the elastic band?

 C. If a mass moves in a straight line and more mass is added, does the inertia increase, decrease, or stay the same?  D. Do you think that the same thing happens to a body in circular motion? Explain

 E. What force is responsible for keeping the water in the cup during the circular motion?

 F. What force is responsible for keeping the cup in circular motion?

 G. Repeat the experiment. Record the time it takes to complete 10 horizontal circles and estimate the length of the radius using a meter stick. Record results and calculate the tangential speed of the cup using the formula on the board.