# Urgent: Springs and Blocks

1. Dec 4, 2003

### Cyto

http://www.myimgs.com/data/Cyto/Physics.jpg

The ramp and the ledge which the box sits on is has a Mu(k) of 0... the spring compression of the block when released from rest is 98cm... i found the height of the ramp being 29m, and the speed at the top of the ramp being 11.8.. i just need help finding the length of the last part before the block stops moving.... the above diagram gives the rest of the info needed

2. Dec 4, 2003

### NateTG

Do you know about work and energy calculations?

Otherwise, you can use kinematics to do this problem since the acceleration caused by friction is constant.

P.S. This is a poor problem because the block will jump at the end of the ramp, and then bounce on the 'flat', and it's unclear whether or how you're supposed to account for it unless the block is affected by some sort of frictionless constraint.

3. Dec 4, 2003

### Cyto

Ya, i understand energy and work calculations, but just don't get this problem and there is supposed to be no friction on the ramp, only on the top

4. Dec 4, 2003

### NateTG

Ok. Consider this:
The block has an x component velocity of vx at the top of the ramp. The acceleration due to friction will be -&mu;mg from there on, so you can use the constant acceleration formulae in one dimension.

A major problem for me is that it's unclear whether you're supposed to account for the jump that the block makes before it starts sliding on the surface. (If you're feeling truly insane, you could deal with the bouncing and spinnning that would occur in that scenario as well.)

5. Dec 4, 2003

### Cyto

I do think I am insane, yes, but would not like to use your crazy methods. Is there a way to use kinetic/potential energy and W=Fad to find the distance.