An electric toy car with a mass of #2 kg# is powered by a motor with a voltage of #8 V# and a current supply of #3 A#. How long will it take for the toy car to accelerate from rest to #6 m/s#?

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Answer 1 · 2018-04-09T15:42:51

The time is #=1.5s#

The power is

#P=UI#

#"Power"="Voltage"xx"Current"#

The voltage is #U=8V#

The current is #I=3A#

The power is

#P=UI=8*3=24W#

The kinetic energy of the car is

#E=1/2mv^2#

The mass of the car is #m=2kg#

The speed is #v=6ms^-1#

So,

The kinetic energy is

#E=1/2mv^2=1/2*2*(6)^2=36J#

Let the time #=(t)s#

#E=Pt#

#"Energy=Power" xx "time"#

The time is

#t=E/P=(36)/24=1.5s#