Question

a car moves with a velocity of 20m/s and reaches to a velocity of 50m/s find out the work done by the car of mass 4500kg​

Answer 1

work done by the car: 4725kj

1. Work done will be change in the energy of the car.

2. Since there is only change in kinetic energy, the work done will be

    final kinetic energy-initial kinetic energy.

3. Initial kinetic energy=1/2*m*(v1)^2

   where v1 is the initial velocity of the car=20m/s

   and m is the mass of the car=4500kg.

4. Final kinetic energy=1/2*m*(v2)^2

   where v2 is the final velocity of the car=50m/s

    and m again,mass of the car.

5. Change in kinetic energy=(1/2*m*(v2)^2)-(1/2*m*(v1)^2)

                                              =1/2*m*((v2)^2-(v1)^2)

                                              =1/2*4500*(2500-400)

                                              =4725000

6. The work done by the car therefore is 4725000j or 4.725*10^3kj