# Work Energy: block w/ friction

1. Dec 15, 2009

### schyuler2

1. The problem statement, all variables and given/known data
Find the initial speed of a block which travels 10m along a horizontal surface if $$\mu$$= 0.40 between the block and the surface before stopping.

2. Relevant equations
$$\Sigma$$W = 1/2mvB2 - 1/2mvA2 + mgyB - mgyA

$$\Sigma$$W = W * dAB * cos (W, dAB)

f = $$\mu$$* N
N= mgsin$$\theta$$

3. The attempt at a solution
so far i have:
$$\Sigma$$W = 0
$$\Sigma$$W = WN + WW + Wf

and

$$\Sigma$$W = WW * dAB * cos (270)
$$\Sigma$$W = WW * 10m * 0

not sure if i'm doing this right or where to go from here

2. Dec 15, 2009

### qnney

This problem requires an equation that you haven't included yet.

$$\Sigma$$F = max
$$\Sigma$$F = Px + fx + Nx + Wx
$$\mu$$ = -a / g