An electric toy car with a mass of #3 kg# is powered by a motor with a voltage of #4 V# and a current supply of #8 A#. How long will it take for the toy car to accelerate from rest to #5/3 m/s#?

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Answer 1 · 2017-04-13T14:04:10

The time is #=0.13s#

Voltage is #U=4V#

Current is #I=8A#

The power is

#P=UI=4*8=32W#

Velocity is #v=5/3ms^-1#

Mass is #m=3kg#

The kinetic energy is

#KE=1/2mv^2=1/2*3*(5/3)^2=25/6J#

But,

#E=P*t#

The time is #t=E/P=(25/6)/32=0.13s#