# An electric toy car with a mass of #3 kg# is powered by a motor with a voltage of #9 V# and a current supply of #3 A#. How long will it take for the toy car to accelerate from rest to #5/2 m/s#?

##### 1 Answer

Jul 16, 2016

#### Explanation:

Given

#m->"Mass of the car"=3kg# #V->"The supplied voltage"=9V# #I->"Current supply"=3A# -
#u->"Initial velocity of the car"=0# -
#v->"Final velocity of the car"=5/2=2.5m/s#

Let

#t->"Time taken to gain the final velocity"=?#

Now we know

#"The Electrical Power supplied"(P)=IxxV#

and

#"The electrical energy(E) consumed in t s"=Pxxt#

#"The gain in kinetic energy"=1/2m(v^2-u^2)=1/2mv^2#

Considering that the supplied electrical energy goes to increase the KE of the car.

So