Working out kinetic energy and speed

AI Thread Summary
To solve the problem of kinetic energy and speed, potential energy (PE) and maximum kinetic energy (KE) are equal in a frictionless system. The maximum loss of PE corresponds to the maximum gain in KE. To find the kinetic energy at point C, subtract the PE at point A from the PE at point C. While kinetic energy allows for calculating speed, it does not provide direction since velocity is a vector quantity. Understanding these energy exchanges is crucial for accurately determining speed in physics problems.
Meezus
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Homework Statement


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Homework Equations

The Attempt at a Solution


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a) I think I just have to work out the potential energy and the maximum kinetic energy would is the same?

c) Once I've found the kinetic energy, I'm able to work out velocity. Would the velocity be the maximum speed?

c) I think I can take the PE from A and the PE C and take them away from each other. With this number I'd have the KE of C which i'd work out velocity with?
 
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Your approach is correct. Thus problem is a simple matter of the exchange of energy between PE and KE.
 
To be accurate...
Meezus said:
the potential energy and the maximum kinetic energy would is the same?
Since there's no friction, the loss in PE equals the gain in KE. So the maximum loss in PE equals the maximum gain in KE.
PE is a relative thing. You cannot say exactly what the PE is at some point unless you have defined some reference value, such as the PE at another point.
Meezus said:
Once I've found the kinetic energy, I'm able to work out velocity. Would the velocity be the maximum speed?
No, velocity is a vector. Given the KE and the mass you can deduce the magnitude of the velocity (i.e. its speed) but not the direction.
 
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