Question

A 10 kg ball is 50 meter above the ground. How fast will it be moving when it hits the ground?

Answer 1

31.3 m/s

Explanation:

v² = v₀² + 2aΔx

v² = 0 + 2(9.8 m/s²)(50 m)

v² = 980 m²/s²

v = √ 980 m²/s² = 31.3 m/s

Notes: ball starts from rest, so v₀ = 0; ball is in free fall, so a = g = 9.8 m/s²; objects in free fall accelerate at the same rate, g, independent of mass.