Question

If and object of 80kg falls from a height of 90m what is the velocity the object will fall with?

Answer 1

We can find the velocity of the object with which it hits the ground from the law of conservation of energy:

$$KE=PE,$$ $$\dfrac{1}{2}mv^2=mgh,$$ $$v=\sqrt{2gh}=\sqrt{2\times9.8\ \dfrac{m}{s^2}\times90\ m}=42\ \dfrac{m}{s}.$$