00:01
We need to find the magnitude of the force that is exerted at the rod, and we also need to find the force exerted by the pin at a onto the a -b -rod.
00:12
So to start solving this problem, we're going to first find the force that is acting on the rod, and it's labeled here in this free body diagram with a vector that is labeled on.
00:28
So start solving for that force, we can say that sum of moments, about a point a, it's equal to zero, and we can write that as the force r times 1 .2 minus the force 60 times 9 .5 is equal to 0.
00:57
And we can take this expression and solve it for the force r.
01:03
And this will give us a value of r that is equal to 475 pounds.
01:21
And for part b, we can say that the sum of forces in the x direction, is equal to 0 and we can use this value that we just calculated for r to solve for the x component of the force at point 8.
01:45
If we can solve for the y component and the x component of the force exerted at the point 8, then that's going to be the force that's also exerted onto the rod baby.
02:01
So we can then rewrite this as the x component of the force at point a plus r times sine of 30.
02:12
Is equal to 0, and we can plug in the known terms to get a of x plus 475 times the sign of 30 is equal to 0.
02:30
In solving this expression for a of x, we'll get a force of negative 237 .5 pounds...