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# Physics - Power watch

1. Hello,

Could somebody please list all of the power equations that are needed for the Edexcel Physics course?
Hello,

Could somebody please list all of the power equations that are needed for the Edexcel Physics course?
I know the equation P=W/t, but what are the others?
3. Outside of that general definition of power, you only need to be aware of electrical power in particular, i.e P=IV and its substitutional derivates.
4. (Original post by sjgriffiths)
Outside of that general definition of power, you only need to be aware of electrical power in particular, i.e P=IV and its substitutional derivates.
So then I can use the equation V=IR and sub that in and those are all i need to know?
5. It may also be worth knowing P = I^2R

This is derived from subbing V=IR into P=IV - sub IR in place of V.
So then I can use the equation V=IR and sub that in and those are all i need to know?
Yep, to get P = I^2 * R = V^2 / R and, of course, also just applying P=E/t in the context of electrical energy rather than mechanical work (although technically it comes back to the same thing with regards to electric fields - what level is this at, out of curiosity?)
I know the equation P=W/t, but what are the others?
You can derive another equation from that:
You already know that W (work done) = Force(F) x Distance(d)
Substitute that in and you get:
P = (Fd)/t
which is the same as
P = Fx(d/t)
speed = distance/time
therefore:
P=Force x Speed
8. (Original post by sjgriffiths)
Yep, to get P = I^2 * R = V^2 / R and, of course, also just applying P=E/t in the context of electrical energy rather than mechanical work (although technically it comes back to the same thing with regards to electric fields - what level is this at, out of curiosity?)
AS and A2, I was just looking for the equations for the entire subject.

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