# Tough inclined plane problem

1. Aug 9, 2014

### slaw155

1. The problem statement, all variables and given/known data
EDIT: I have solved it entirely myself.

2. Relevant equations

3. The attempt at a solution

Last edited: Aug 9, 2014
2. Aug 9, 2014

### haruspex

Even so, you are required to post your attempt, so far as it goes.

3. Aug 9, 2014

### slaw155

I have worked it out entirely using my own self-determined methods.

Last edited: Aug 9, 2014
4. Aug 9, 2014

### dean barry

Without friction the initial KE should equal the final PE.

5. Aug 9, 2014

### HallsofIvy

Staff Emeritus
With friction, final PE should equal initial KE minus energy lost to friction- the friction force times the distance traveled.

6. Aug 9, 2014

### dean barry

So :

The initial KE - the final PE = the energy lost to friction
= ( ½ * m * v ² ) - ( m * g * h )
( Joules )

Over the length of the incline, the energy lost to friction = ( constant ) friction force * distance travelled
( the length of the incline = 22.0 / ( sine 2.5 ° ) )

So, then, the friction force must equal ( ( initial KE ) - ( final PE ) ) / distance travelled