00:01
So, let us start with the concept which we are going to use here for this question.
00:07
So, we know that summation of moment about any of the point p, let's say, is always equals to zero and moment can be given by the force vector into the distance vector from where it is about to be moved.
00:22
So, according to question we need to determine the direction theta for the value of theta is varying from zero degree to 180 degree of the force l, so that it produced in part a the maximum moment about a point.
00:41
So, let's have a look to the figure first.
00:43
So, this is what the figure in which you can clearly see that.
00:47
This is what the point a about which the maximum moment will be there and accordance to the a part.
00:55
So, we have to find the value of theta.
00:58
Now, also we have given the force f is equals to 40 ib, then a equals to 8 feet and b is equals to 2 feet which you can clearly see throughout the diagram.
01:15
While this is what the force which is at an angle of theta which basically we have to compute.
01:22
So, let's get started with solution.
01:25
So, first of all we use the concept and apply the moment at a point.
01:34
So, since we know the moment at point a this should be equals to force into the distance from that point.
01:40
So, clearly if we try to look to the figure, so this force will have the two components, one will be the vertical, one will be the horizontal one.
01:50
So, the vertical, sorry the horizontal one will be f cosine of theta that means f cosine of theta multiplied by the distance.
02:03
If you see from this point, its distance is b.
02:06
So, obviously this is going to be b plus of f sine of theta times of the distance is capital of a or you will say small a, nothing worries about this, small a is the distance...