Question

From a building of height h = 16.5 m, you throw a ball of mass of m = 335g downwards with an initial speed vi = 5.7 m/s. What is the final speed vf that the ball is traveling when it hits the ground?

Answer 1

From the conservation of energy:

$$0.5mv_f^2=0.5mv_i^2+mgh$$

$$v_f^2=v_i^2+2gh=5.7^2+2(9.8)(16.5)$$

$$v_f=18.9\frac{m}{s}$$