Physics: Electric Circuits

[basketballakev]

Which formula represents the time it takes to accelerate a car of mass m from rest to a speed v, using an electric motor with voltage V and drive current I?

A. t = 2IV/mv^2

B. t = 2Iv/mV

C. t = mv^2/2IV

D. t = mV/2Iv

Since P = IV & KE = 1/2mv^2, I set the equation up as follows;

IV = 1/2mv^2

I'm just a bit confused as to how time t is inserted into this equation. The answer would be C. Thanks a lot!

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[FutureScaresMe]

Tricky

since P = IV = PE/t
PE = IVt
IVt = 1/2mv^2

 

[majik1213]

so power is energy over time, right? P = K.E. / t ==> t = K.E. / P ==> C is the answer