Answer to Question #243381 in Physics for juju

Question

Find the power output of the engine of a 1200 kg car while the car accelerates from 30 km/h to 100 km/h in 10 s.

Answer 1

The power is how quickly work can be done. According to kinetic energy theorem, the work is

$$W=\Delta E_K=\frac m2(v_2^2-v_1^2).$$

Hence, the power is

$$P=\frac Wt=\frac m{2t}(v_2^2-v_1^2)=42.13\text{ kW}.$$