An electric toy car with a mass of #3 kg# is powered by a motor with a voltage of #8 V# and a current supply of #11 A#. How long will it take for the toy car to accelerate from rest to #7 m/s#?

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Answer 1 · 2017-03-24T07:09:24

The time is #=0.84s#

Voltage is #U=8V#

Current is #I=11A#

The power is

#P=UI=8*11=88W#

Velocity is #v=7ms^-1#

Mass is #m=3kg#

The kinetic energy is

#KE=1/2mv^2=1/2*3*7^2=73.5J#

But,

#E=P*t#

#t=E/P=73.5/88=0.84s#