# How do i find applied force if it not given?

1. Sep 2, 2007

### puni12

how do i find applied force if it not given?
how do i find force of friction if coefficient of friction is also not given?
how do i find coefficient of friction of objects on 3 different surfaces?
(what should be the variable?)
thanks so much

2. Sep 2, 2007

### happygiant

the way is same, resolve the forces, get the normal. if co-oefiicient is not given, its very simple, you cant find. for three surface, if there are less than 3 equations, then the solution is also simple. you cant help.

3. Sep 2, 2007

### happygiant

make your question a bit clearer. frame it in a for of sum

4. Sep 2, 2007

### Staff: Mentor

The particulars of how you'd solve for applied force, or friction, or the coefficient of friction depend on the exact problem. But usually it will involved applying Newton's laws and the simple model of friction in terms of $\mu$ and normal force.

Pick a specific problem and give it a try.