# Momentum on a slope question

DavidHarmon

## Homework Statement

A block of mass m = 2.80 kg slides down a 30.0° incline which is 3.60 m high. At the bottom, it strikes a block of mass M = 7.00 kg which is at rest on a horizontal surface, Fig. 7-41. (Assume a smooth transition at the bottom of the incline, an elastic collision, and ignore friction.)
http://img141.imageshack.us/img141/4472/741ue2.gif [Broken]

(a) Determine the speeds of the two blocks after the collision.
Lighter Block:
Heavier Block:

(b) Determine how far back up the incline the smaller mass will go.

## Homework Equations

v=final velocity
u= Initial velocity
a=acceleration
s= Displacement
v^2=u^2+2as

m1u1+m2u2=m1v1+m2v2

## The Attempt at a Solution

I resolved to find acceleration perpendicular to the plain of motion and also the displacement, but as i was not given an initial velocity i cannot find out the final velocity of the small block as it hits the large block

Does anyone have any ideas as to how i would go about solving this question?

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