(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The two masses (m_{1}= 5.2 kg and m_{2}= 2.6 kg) in the Atwood's machine shown in The Figure are released from rest, with m_{1}at a height of 0.79 m above the floor. When m_{1}hits the ground its speed is 1.7 m/s.

Assuming that the pulley is a uniform disk with a radius of 12 cm, outline a strategy that allows you to find the mass of the pulley.

Determine the pulley's mass.

2. Relevant equations

Rotational Kinetic Energy: K + (1/2)Iw^{2}

Conservation of Energy: K_{i}+ U_{i}= K_{f}+ U_{f}

3. The attempt at a solution

I am more or less stumped on this problem. Information that is known is that v_{0}= 1.7 m/s and v_{f}= 0. The E_{i}= mgh (I think since the system starts at rest and m_{1}has Gravitation Potential Energy). E_{f}= (1/2)mv^{2}+ (1/2)Iw^{2}. All this is speculation since I am grasping at a way to solve this problem.

Also, from looking at other related problems people tend to find acceleration through the Kinematics v^{2}- v_{0}^{2}/2(x - x_{0}). However, I am not sure how to apply the acceleration of m_{1}, all I know is that it translates through the pulley system.

Another possible acceleration I found was a = [(m1 - m2)/(m1 + m2)]g. This formula brought up a different acceleration than the previous, but once again I am not certain how to apply it.

Reassurance that I am on the right route, and a hint would be greatly appreciated.

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# Homework Help: Atwood's Machine

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