Determine the speeds of the 2 masses

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Homework Help Overview

The discussion revolves around a physics problem involving the determination of speeds of two masses connected by a pulley system. Participants are examining the concept of potential energy in relation to the pulley and its assigned reference point.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the reasoning behind assigning the initial potential energy of the pulley as zero. There are discussions about the implications of potential energy being arbitrary and how it affects the calculations.

Discussion Status

There is an ongoing exploration of the role of potential energy in the problem. Some participants have offered insights about the cancellation of potential energy terms in the equations, but there is no explicit consensus on the initial assumptions regarding the pulley’s potential energy.

Contextual Notes

Participants are navigating the implications of potential energy reference points and how they relate to the overall energy conservation in the system. The discussion reflects a need for clarity on the assumptions made in the problem setup.

Neon32
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Homework Statement


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Homework Equations

The Attempt at a Solution


Here is the solution in the answers sheet. Why the initial potential energy of the Pulley (M) = 0?

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The initial potential energy is not zero in the calculation.

It would not matter - potential energies are arbitrary, only differences in potential energy (before/after) matter. The difference is not zero.
 
mfb said:
The initial potential energy is not zero in the calculation.

It would not matter - potential energies are arbitrary, only differences in potential energy (before/after) matter. The difference is not zero.
you don't get what I mean.
He put the potential zero of the pulley =0. Why is that? The pulley is at a height so it accuires potential energy.
 
Ah, that.
Same thing: It does not matter, as its height does not change. Any potential energy you assign to it would appear on both sides of the equality, and cancel.
 

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