S.O.S. Mathematics CyberBoard

[wolverine0206]

The problem comes with a diagram at
http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=21023924&imageID=1304588390

It uses the same picture as problem 5 but with changes. Instead of having a string, I now have spring with a force constant k. The length of the spring is now L. Assume that x is much less than the length (L)

a) Determine the amount of stretch at point C.



b) Assume the ball is moving fast enough to complete a full circle. Under the conditions would you expect the ball to compress the spring at point A? Explain.


Hint: You will need to consider dynamics and energy.


a) How do I do it? Am I suppose to use B as my initial point and find energy change from B to C? Then somehow, am I suppose to find velocity with the circular motion. The answer key says x = 3mg/k so I think that both gravity and the force of the spring contribute to this, but how?

b) I know at A I have an acceleration towards the center pointing down, and gravity also acts downward. How do I know when the spring will compress though. The answer key says that v<SQRT(gL). gL is the work done by gravity divided by the mass. Why take its square root?

[ang0123]

Cannot view the picture...