Calculate velocity of block down a ramp using energy conserv

[Scatteredheroes]

Homework Statement

A 2kg block slides down a 3 m long ramp that is inclined at 40 degrees. The coefficient of friction is .2

What is the velocity when it hits the bottom of the ramp?

Homework Equations

Kinetic = 1/2 mv^2
Potential = mgh
Work of friction: Fnμ*(displacement)

The Attempt at a Solution

1/2mv^2 + mgh = 1/2mv^2 + mgh - Fnμ*(displacement)

v = 8.237.
[/B]
I don't think that's right, because I didn't take into account the angle. What do I need to do?

 

[Simon Bridge]

Draw a picture.

 

[Gabriel Bello]

You can start by drawing a free body diagram (those always help).

 

[Simon Bridge]

Not in this case ... a fbd won't tell OP the correct height the block falls.