Confusing forces, and friction problem

[johswill]

Homework Statement

My friend posed this problem to me about a week ago, and I haven't been able to figure it out, it is: So, we've got a block with mass m on an inclined plane of 30 degrees above the horizontal. It is placed at a height of 2.5 m. The coefficient of friction is 0.4. It slides down 5m. What is the final velocity?

Homework Equations

F=ma, Ff=u*Fn

The Attempt at a Solution

I have been able to get everything right, I'm just not sure how to do if it there is not a time component added into the problem, and my friend said you didn't need time.

 

[rock.freak667]

Try using conservation of energy. All of the gravitational potential energy goes into kinetic energy and energy in overcoming friction.