- 3

- 1

**Summary:**Non - ideal pulley question, should be easy but has got me good

Hey guys, looking for some help on this pulley question. It involves torque, and works with newton's 2nd law in conjunction with a non-ideal pulley.

Text of question:

" When the motor in the figure below lowers the

*m*= 1160kg mass, it produces a tension of 1.06E+4N in the cable on the right side of the pulley. The pulley has a moment of inertia of 75.7kgm^2 and a radius of 0.747m. The cable rides over the pulley without slipping. Determine the acceleration of the

*m*= 1160kg mass. Use g=9.81m/s^2. "

Diagram:

Attempt

I found free body diagrams for both the mass and the pulley, and boiled them down to two equations, two unknowns as follows -

T2 = mg-ma

and

(r^2)T2 - (r^2)T1 = Ia

But when I added the equations together (subbed the first into the second), I got a final answer a = 0.602 m/s^2 , which was wrong.

*Note - my final formula was:

a = (r^2)(mg - T1) / (I + (r^2)m)

can anyone help me out?

**[Moderator's note: Moved from a technical forum and thus no template.]**

Last edited by a moderator: