- #1

- 4

- 0

**[SOLVED] A block hits a patch of friction**

A block of uniform density, length L and height h << L, starts from rest at the top of a hill of height H, slides down. At the bottom there is a flat surface of length greater than L, and then a rough patch with sliding coefficient [tex]\mu[/tex]

I figured out the first part, which is to find the height such that the block comes to a stop the instant the entire block is on the rough surface. The answer is [tex]Hcrit=\frac{L\mu}{2}[/tex] Is this right?

Now I need to find what happens if the hill has a height H < Hcrit.

I think the block still has follows simple harmonic motion, and obviously from conservation of energy it has a speed [tex]\sqrt{2gH}[/tex] at the bottom of the hill, but for some reason I'm having huge trouble finding

**the distance that the leading edge of the block travels across the surface with friction before it comes to a stop.**

I don't know where to go from here. Some hints, please? :)