Question

5. c) Find the total energy of a moving object of mass 6.3 kg and momentum 11.5 x 10 kgms^-1

Answer 1

Express velocity in terms of momentum:

$$v=p/m.$$

The kinetic energy:

$$E=\frac12mv^2=\frac12m\bigg(\frac pm\bigg)^2=\frac{p^2}{2m},\\\space\\ E=\frac{11.5·10}{2·6.3}=9.13\text{ J}.$$