Question

If the mass of a car is 1000 kg, then the amount of work to be done to increase its velocity from 30 ms–1 to 40 ms–1 is

Answer 1

Work done is equal to change in kinetic energy as per work energy theorem.
$w = ke2 - ke1$
Here je1 and ke2 are kinetic energy at initial and final conditions respectively.

So ke2=1/2×1000×40^2=800000 joule.
similarly,ke1=1/2×1000×30^2=450000joule.

So work done=
800000-450000=350000 joule or 3.5×10^5 joule.

Thanks.
Tripathy