Question

You read about a rope and pulley machine that was able to produce equal amounts of output work and input work. was this a realistic example? why or why not?

Answer 1

Not realastic because this could only happen in the absence of friction, and friction is everywhere in the real world.

Answer 2

hi,that s good point,plus
1)we should consider reaction of pin (which exist of pulley)
2)consider friction of material (for rope)
3)inertia of pulley
4)what kind of pulley we use (Double,constant,parallel,...)
5)we should consider is this an equilibrium processes or not.
6)and some thing else (wight of rope)
7)reaction torque of pulley
8)and...
some where instead of pulley we should use roll boring and boring
and...