00:03
Hello, we draw a diagram.
00:06
This is our wall, this is our hinge and our bar of length 8 meters.
00:14
The bar is supported by this rope tension t.
00:22
There is another weight of 10 kilograms whose weight is going to be 9 .8 times 10 kilograms attached here.
00:34
The person, the center of mass of the beam itself, or center of the center, of weight 16 newtons, the person standing here has a mass of 70, so their weight is 70 times 9 .8 and the distance from the beam is 2 .5, there is hinges 2 .5 meters.
00:59
So we resolve the tension t to get its vertical component, which is t, sine 53 and horizontal which is t cost 53.
01:20
The angle here is 53 degrees.
01:24
So applying the principle of moments or taking moments about the hinge which we call a.
01:34
Moment of the person's weight will be 79 .8, the weight times the distance, plus that of the center of mass of the beam.
01:49
Its distance is 4 meters because it is halfway between.
01:52
The entire thing, the entire beam is 8 meters long.
02:00
Moment of this, which is 10 .9 .8 also times its distance from the hinge.
02:21
That should be equal to the moment of the perpendicular component of tension.
02:28
That is the perpendicular of tension times its distance 8 from the hinge...