An electric toy car with a mass of #1 kg# is powered by a motor with a voltage of #12 V# and a current supply of #15 A#. How long will it take for the toy car to accelerate from rest to #5 m/s#?

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Answer 1 · 2017-10-03T06:24:41

The time is #=0.069s#

The power is

#P=UI#

The voltage is #U=12V#

The current is #I=15A#

The power is

#P=UI=12*15=180W#

The kinetic energy of the car is

#E=1/2mv^2#

The mass is #m=1kg#

The speed is #v=5ms^-1#

so,

#E=1/2*1*(5)^2=12.5J#

Let the time #=(t)s#

#E=Pt#

#t=E/P=(12.5)/180=0.069s#