00:01
So we are given that there are two weights acting downwards, 20 .5 newton and 112 newton.
00:11
From here on, we'll just combine these two into a single force of 132 .5 newton.
00:19
Now this is the weight of the hand and the weight combined.
00:22
Now, the bicep fore arm is raised at an angle of 43 degrees from the horizontal.
00:29
Because the bicep force acts perpendicular to it, now we can see that because this is 40, this angle is 43 degrees, this angle must be 90 minus 43 degrees because this is a right angle.
00:51
Now because this is a right angle, we know that this angle must be 90 minus.
00:59
Let's say if this angle is alpha, this would be 90 minus alpha and that would be 90 minus alpha and that would be 90 minus of 90.
01:07
D minus 43 which would be 43 degrees hence this angle is 43 degrees now let's call this vector b for bicep let's write down the vector form of vector b now the x component of vector b is negative but the y component is positive and because this angle is 43 degrees its x component would be its magnitude b which is 230 multiplied by the magnitude is 232 newton multiplied by sine 43 degrees i had but because this is negative we put a minus here let me erase this part here yeah that is 232 plus our y component would be 232 cost 43 and because it is positive we just leave it like that this turns out to be minus 158 0 .2 to 1 .2 y hat plus 169 .67 j hat.
02:28
Now let's say our elbow force is vector e, force e...