Excellent.

I’m confused; does this mean that it takes MORE sideways force to move the block than it would if there was no vertical force? For example, wouldn’t the block move if F1 = 0N and F2 = 2N?

Excellent. You have asked the $64K question.

If you **assume** that the coefficient in any given direction is not increased by force components not in that direction, then the answer is that the block will start to slip when F[sub]2[/sub]=2 Newtons. See attached “solution.pdf”.

However, these 2 assumptions:

1: linear change in mu for angles between 0 and pi/2, and

2: mu is not increased by force components not in direction being considered

are I think open questions.

In FRC, there are wheels which are said to have different mu in the forward and sideways directions. I have looked but never seen any test data to show what happens when force is applied at a variety of angles between 0 and pi/2.

*

solution.pdf (42.7 KB)

solution.pdf (42.7 KB)