00:01
Here the free body diagram is as follows.
00:04
So this is the free body diagram.
00:06
This is box a and this represents box b.
00:11
There is angle 60 degree here and here it is 30 degree.
00:16
So there is 40 sign 30 degree and 40 course 30 degree components on block b and 60 sign 60 degree and 60 cost 60 degree components on block a.
00:29
Here we are given mass of block a is equal to 60 pound mass, mass of block b is equal to 40 pound, coefficient of kinetic friction is given which is 0 .1.
00:46
Now from the free body diagram we can say that here normal reaction n a, that is this value is equal to mass of block a into cost, pos -theta.
01:01
Upon substituting the values, here ma is 60 lb into cos, here theta is 60 degree.
01:10
So this turns out to be 30 lb.
01:14
So 30 pound mass is the normal reaction of block a.
01:18
Now the friction force at block a is given by friction force f .a is equal to the coefficient of kinetic friction into the normal reaction of block a.
01:36
So this is equal to 0 .1 into n .a is 30 lb, which we have found out just now upon solving this turns to be 30 pound mass, 30 lb.
01:47
Also, here the normal reaction of block b is equal to mass of block b into cos theta.
01:56
Mass of block b is given which is 40 lb into course here.
02:01
The block b makes an inclination angle of 30 degree.
02:06
Upon solving we will get a normal reaction of block b to be 34 .64 pound mass.
02:13
Now we calculate the friction force at block b.
02:21
The friction force at block b is given by fb is equal to the coefficient of kinetic friction into the normal reaction of block b.
02:31
This is equal to 0 .1 into the normal reaction of block b is 34 .64 pound mass.
02:39
Upon solving we will get 3 .46 pound mass as the friction for set block b...