# Homework Help: Solving Differential Equations for Inclined Plane.

1. Feb 10, 2012

### sergej21

1. The problem statement, all variables and given/known data

http://img192.imageshack.us/img192/6482/asderl.jpg [Broken]

Find S(t).

2. Relevant equations

I managed to find these equations, but dont know how to solve them completely.

mx=Rsinφ
my=Rcosφ-mg
xtgφ+y=h
x(0)=0; x(0)=0; y(0)=0; y(0)=h

3. The attempt at a solution
Need to find s(t). Is S=(x^2+y^2)^0.5?

Thank you!

Last edited by a moderator: May 5, 2017
2. Feb 10, 2012

### ehild

According to the picture, s=(x^2+(xtanφ))^0.5.

ehild

3. Feb 10, 2012

### sergej21

Last edited by a moderator: May 5, 2017
4. Feb 11, 2012

### ehild

The question : what is R. If it is an arbitrary force, perpendicular to the surface, you have done. If it is the normal reaction force the slope exerts on the block, R=mg cos(φ).

The solution of the problem "block sliding down on slope" is much easier with a coordinate system where the axes are aligned parallel with and perpendicular to the slope.

ehild