00:01
Okay, so this is the force diagram for the crates.
00:06
And assume that the crates is in equilibrium, therefore the net force along the x -y direction should be equal 0.
00:13
So we have f minus p is equal 0, which means that f is equal to p.
00:16
F here is the friction on the crates, and p here is the force applied by the person.
00:22
And on y direction, we have n minus w is equal 0, which means that n is equal to w.
00:28
N is the normal force on the crates, w is the gravity of the crates.
00:31
And when the friction, in this case, can be equal to mu .sn, which is equal to mu.
00:36
M .s.
00:36
Here is the coefficient of the static friction.
00:40
So eventually you have p is equal to mu s .w.
00:43
And when you have mu .s is equal to 0 .5, w is equal to 150 pounds.
00:46
If we plug in battery equation with these values here, eventually you have the force p is equal to 75 pounds.
00:53
So now let's assume that the crate slides before, oh, sorry, here should be tipping, okay? so my assumption is that assume that the, crates, slides before tipping.
01:09
So now we can apply the moment at point a.
01:12
Consider counterclockwise moment is positive, clockwise moment is negative.
01:17
So we have p times 3 feet minus w times x is equal 0...