00:01
So we know that the wall was frictionless.
00:05
And so to find the maximum frictional force, we simply just need to find the normal force exerted by the floor.
00:12
So we can say that the sum of forces in the y direction equals zero.
00:16
And this would say n sub 2 equals w sub 1 plus w sub m.
00:22
And this is equaling 160 plus 740, so 900 newtons.
00:28
So this would be the magnitude of the normal force, inserted by the floor on the ladder.
00:35
So we can say that the maximum friction is going to be equal to the coefficient of static friction.
00:42
This would, of course, give us the maximum friction because the coefficient of kinetic friction is always less than the coefficient of static friction times.
00:51
So it's mu sub s times n sub 2.
00:53
And this would be 0 .4 times 900.
00:57
And this is giving us 360 newton.
01:00
So this would be your answer for part a.
01:01
This would be the maximum frictional force and this occurs between the point of contact of the ladder and the floor.
01:10
For part b, they want us to find ed sub 1.
01:13
So this would be the normal force that is exerted by the wall on the ladder...