# Time taken for an object to slide down a plane given μ, s and θ

1. Mar 20, 2013

### PhysicsThrow

1. The problem statement, all variables and given/known data
Find the time taken for an object to slide down an inclined plane given the coefficient of friction, length of slope and angle of incline.
The coefficient of friction is 0.3.
The angle of incline is 30°.
The length of the slope is 6m.

2. Relevant equations
F=μN
F=(mg)sin(30)
N=(mg)cos(30)
F=ma

s=ut+1/2at2?
3. The attempt at a solution
Completely stuck. I assume I must calculate the mass of the object first? Using F=μN some how? Then I can calculate the acceleration of the object with F=ma? Then I can find the time taken to slide down with s=ut+1/2at2?

2. Mar 20, 2013

### Staff: Mentor

You won't need the mass. But you will need the net force. (Symbolically, not with numbers at this point.)
Yes, where F is the net force.
Yep.

3. Mar 20, 2013

### PhysicsThrow

Ahah! I think I have it then!

ma = mg(sin(30)+-0.30cos(30)
ma = m*2.36
so, a = 2.36

4. Mar 20, 2013

Good!