(sorry about another topic but this week's HW is hard @_@)(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

A circular-shaped object has an inner radius

of 6 cm and an outer radius of 22 cm. Three

forces (acting perpendicular to the axis of

rotation) of magnitudes 13 N, 28 N, and 13 N

act on the object, as shown. The force of

magnitude 28 N acts 40◦ below the horizontal.

Find the magnitude of the net torque on

the wheel about the axle through the center

of the object. Answer in units of N · m.

2. Relevant equations

Torque = Fd sin (th)

3. The attempt at a solution

I ignored the mass because the teacher didn't mention anything about reading over the moment of intertia section in our textbook, but I think she was wrong... Anyway:

Clockwise as the positive direction.

Net Torque = (13 * 0.28) + (13 * 0.28) - (28 * 0.06 sin 40)

Net torque = 6.200116816 m*N (WRONG)

T_T I tried reading the section, but it gave me an equation (Net Torque = Moment of intertia * angular acceleration) I couldn't do anything with, as I didn't know how to solve for the angular acceleration.

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# Homework Help: Torque on a compound wheel

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