Question

A safe is hurled down from the top of a 130 m building at a speed of 11.0 m/s what is it’s velocity as it hits the ground?

Answer 1

S = V0 t + 1/2 g t^2 standard formula for distance traveled

130 = 11 * t + 1/2 * 9.8 * t^2

26.5 = 2.24 t + t^2 divide by 4.9

t^2 + 2.24 t - 26.5 = 0 rearranging

t = 4.15 time to reach ground

V = V0 t + g t = 11 * 4.15 + 9.80 * 4.15 = 86.3 m/s velocity as hits ground

Check:

11 * 4.15 + 4.90 * 4.15^2 = 130 distance traveled