Question

power supply to change the velocity of a car from 5 metre per second to 10 metres per second in 4 second is 100 watt find the work done on the car during this time If the mass of the car is 1000 kg find its initial and final kinetic energy​

Answer 1

Answer:

work done is equal to 400 joules and kinetic energy before is 50 kilojoules and after is 12.5 kilojoules.

We know that,

work done = power x time

=> work done = 100 x 4 = 400 joules

kinetic energy = mv²/2

Hence kinetic energy before power application,

E₁ = 1000  x 10²/2

= 1000x 50

= 50 kilojoule

Kinetic energy after applying power,

E₂ = 1000 x 5²/2

= 500 x 25

=12500

= 12.5 kilojoules