Working out kinetic energy and speed

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 1K views
Meezus
Messages
57
Reaction score
0

Homework Statement


UwBg1i5.png

Homework Equations

The Attempt at a Solution


[/B]
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?
 
Physics news on Phys.org
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.