Question

A 50 kg shell is fired from a cannon on Earth's surface with a potential energy of 196,000 J. What is the shell's maximum height?

Answer 1

By the definition of the potential energy, we get:

$$PE=mgh,$$ $$h=\dfrac{PE}{mg}=\dfrac{196000\ J}{50\ kg\cdot9.8\ \dfrac{m}{s^2}}=400\ m.$$