A horizontal beam of weight W is supported by a hinge and cable as shown. The force exerted
on the beam by the hinge has a vertical component that must be:
Answer is nonzero and up.
The pull P is just sufficient to keep the 14-N block and the weightless pulleys in equilibrium
as shown. The magnitude T of the tension force of the upper cable is:
Answer is 16 N.
1. τ=r x F
The Attempt at a Solution
1. Not quite sure why the answer for this one is nonzero and up. Shouldn't the cable already have a tension force in the y direction that cancels out the weight of the beam? Then the only force that the hinge needs to exert is in the positive x direction to counteract the tension in the y-direction. Can someone shed some light on this one?
2. I'm having a bit of trouble setting up a free-body diagram for this one, but I do know that pulleys reduce the required pulling force by a factor of 2, and since there are three pulleys it reduces the pulling force by a factor of 8. 14/8 is 1.75, which using T=mg+P equals 15.75N for T, or 16 N. Is this logic even correct? And if so, could someone help me set up the FBD so I can prove my logic?