# Force: A Wooden Block

1. Apr 16, 2007

### NaZer

1. The problem statement, all variables and given/known data
A 5.0-kg wooden block is placed on an adjustable inclined plane. [ U(mu)k=0.25 and U(mu)s=0.45]
a.) What is the angle of inclined above which the block will start to slide down the plane?
b.) At what angle of incline will the block slide down the plane at a constant speed.

~Now I know how to set up the problem (i think), but I haven't the slightest clue how to approach this. If someone wouldn't necessarily give me the answer but tell my how to tackle it. Or explain it to me, that would be ideal. Now since you have to show kind of poking at the problem, here ya go.

2. Relevant equations

3. The attempt at a solution
http://img401.imageshack.us/img401/276/physics311ua2.th.jpg [Broken]
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited by a moderator: May 2, 2017
2. Apr 16, 2007

### Mathgician

Hint: Trigonometry

read the question carefully, it says when it starts sliding. What does that tell you?

Last edited: Apr 16, 2007
3. Apr 16, 2007

### NaZer

How would you use Trig.? Isn't there too many unkowns. In order to use Trig, i would need some sides or angles.

4. Apr 16, 2007

### Mathgician

relate the directions of the arrows you just drew with trig and the angle of the incline. try to make the sum of force equations for the Y and the X direction

5. Apr 16, 2007