00:02
Hi, we have a block on the ramp and we need to determine whether the block is in equilibrium and find the value of the frictional force.
00:10
So first of all, let's find out this theta angle here from the triangle given there.
00:16
Theta is equal to inverse tangent of 3 over 4.
00:21
From there, here we have 4, here we have 3 in that little triangle given in the figure.
00:27
So from here we get 37 degrees which we are going to use.
00:33
And on the block we have several forces.
00:36
So let's construct the force diagram or the free body diagram.
00:39
First of all, there is gravitational force that has here angle theta.
00:44
So there is a fg sine of theta force down the ramp and that is perpendicular to the ramp.
00:52
Downwards we have fg cosine of theta.
00:56
There is the normal force and there is the force of 100 newton pushing upwards.
01:03
And we also have frictional force.
01:06
Now we need to decide if the frictional force is upward or downward.
01:09
That will depend on the value of the gravitational force times sine of theta here.
01:15
So let's first calculate that.
01:17
Fg sine of theta is equal to 300 newton which is given the weight of the block times sine of 37 degrees...