1. Nov 16, 2005

bochai

Simple Harmonic Motion
A block of mass M = 10 kg is hanging, at rest, from a spring with a force constant of 250 N/m. There is also a very small penny sitting on top of the block. (Note: The penny is not stuck to the block and can leave the surface of the block.) The block is now pulled down a distance of 0.8 m held there and then released. Note: Assume that the mass of penny << mass of bock
Part A
Answer the following five questions by analytical means (i.e. math methods). Assume that Simple Harmonic Motion holds.
1) angular frequency of the system
2) amplitude of vibration
3) period of vibration
4) linear frequency of vibration
5) maximum acceleration the block experiences
Note: Do not consider the penny for the above calculations.
Part B
Now considering the penny as part of the system but assuming the mass of the penny is so small compared to the block that the Simple Harmonic Motion of the block is not affected by the penny.
Answer the following four questions by analytical means (i.e. math methods).
6) Why will the penny leave the surface of the block? Explain.
7) At what time will the penny leave the surface of the block after the block is released?
8) At what position, x, will the block be when the penny leaves the surface?
9) What will be the speed of the block when the penny leaves the surface?
(Part A is easy, but I'm not sure how to approach part B)

Last edited: Nov 16, 2005
2. Nov 16, 2005

Physics Monkey

We can't help until you've shown some of your own work. What have you thought about so far?

3. Nov 17, 2005

bochai

I think the penny will leave after the system passes the equilibrant point, when the sping gaives the block a downward acceleration which is greater than the acceleration of the penny due to the gravity. I dont know if it is right, please help.

Last edited: Nov 17, 2005
4. Nov 17, 2005

Staff: Mentor

That's the right idea. Now you just have to figure out when and where will that happen.