# Work doneWatch

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#1
Can someone please explain what the following equations are used for as I don't understand

E=1/2kx
W=Fx

They're both energy = force x distance but I don't understand why one involves dividing by two

thanks
0
5 years ago
#2
(Original post by LeaX)
Can someone please explain what the following equations are used for as I don't understand

E=1/2kx
W=Fx

They're both energy = force x distance but I don't understand why one involves dividing by two

thanks
The first equation looks like it may the potential energy stored by extending a spring. It looks like it may be missing a squared term:

PE = kx2/2
0
#3
(Original post by uberteknik)
The first equation looks like it may the potential energy stored by extending a spring. It looks like it may be missing a squared term:

PE = kx2/2
ohh I see
so if we had to work out the power supplied to keep a spring in motion which would we use?
0
5 years ago
#4
(Original post by LeaX)
ohh I see
so if we had to work out the power supplied to keep a spring in motion which would we use?
If there were no losses as the spring oscillates then the spring would act as if in perpetual motion. i.e. the only energy needed to set the spring in motion would be the energy required to extend the spring in the first instance.

Since power is Energy/time, the power needed will depend on the time it took to extend the spring.

On the other hand, if there are losses in the system (air resistance, heat losses etc), then energy would need to be added to the system in order to overcome the losses and keep the spring in motion.

You need to post the full question if you need a definitive answer.
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