I believe what they are trying to say is when the disk spins, it is pushing the surface in the opposite direction of which it is moving. Think about it: when you push against the ground, you move in the opposite direction of your push. Therefore, the friction is in the opposite direction of...
ty Imperitor i got it
it doesn't slacken as he jumps - it adds more force to the equation
therefore, it = ma(jumper) + m(7.7)(jumper adding force)
and if i plug those in it yields the correct answer :D
A 65.0 kg tightrope walker stands at the center of a rope. The rope supports are 10 m apart and the rope sags 10.0^\circ at each end. The tightrope walker crouches down, then leaps straight up with an acceleration of 7.70 {\rm m}/{\rm s}^{2} to catch a passing trapeze. What is the tension in...