# Simple Harmonic Motion

1. Homework Statement

http://www.physics.umd.edu/courses/Phys122/Noyes/HW/hw1.pdf (pg 3)

2. Homework Equations

Im guessing that E = K + U has something to do with it

3. The Attempt at a Solution

Not really sure where to start..I tried a few approaches but none of them got me anywheres E = 1/2mv^2 + 1/2 kx^2..but im missing too many things..

Any help?

Related Introductory Physics Homework Help News on Phys.org
when the bullet colides, it sticks. This means that energy is not conserved but something else is.

by the way, the fact that the clay sticks and that the collision is therefore perfectly inelastic is one of those "assumptions"

Last edited:
conservation of linear momentum?

yes. now you can use that in combination with energy.

so I have $$\frac{mv +Mv_2}{m+M} = v_f$$ where $$Mv_2$$ is going to be 0 since it is at rest?

and $$E=1/2mv^2 + 1/2kx^2$$

Do i let m = m+M? and will 1/2kx^2 be 0 since the block can be considered to be at point x=0?...set it to zero and solve for v?

you actually dont need to use energy untill you are ready to find the amplitude. You already have enough information to find the velocity.

So imediately after the collision, the spring has no effect on the velocity?

that's correct. two ways to understand that
1) imediately after colision, spring is not compressed and therefore applies no force.

2) even if it were compressed, a force causes an acceleration which only changes velocity of some period of time.

Solved it..Thanks for the help

good job, np