Question

Car mass of 1167 kg accelerates on a flat highway from 10.0 m/s to 28.0 m/s. how much work does thr car's engine do on the car ?

Answer 1

For the work-energy theorem, the work done by the engine on the car is equal to the variation of kinetic energy of the car:
$W= K_f-K_i=\frac{1}{2}mv_f^2 - \frac{1}{2} mv_i^2$
where m=1167 kg is the mass of the car, $v_i=10.0 m/s$ is the initial speed and $v_f=28.0 m/s$ is the final speed.

Putting numbers into the equation, we find:
$W= \frac{1}{2}(1176 kg)(28.0m/s)^2- \frac{1}{2}(1167 kg)(10.0 m/s)^2=4.0 \cdot 10^5 J$