How do friction formulas work in physics?

[izmeh]

Originally posted by chroot
F is the force, o is the angle, 21 degrees. Think about it this way: the horizontal component of the force is F cos(o), while the vertical component is F sin(o).

- Warren

so you sub .57 in for F? then multiply it by cos or sin

 

[chroot]

Originally posted by izmeh
so you sub .57 in for F? then multiply it by cos or sin

No. F is the magnitude of the force, the quantity you're trying to find. 0.57 is [mu].

Solve this equation for F:

F cos(21 deg) = [mu] (m g + F sin(21 deg))

- Warren