Question

a man drops a 10kg rock from the top of a 5m ladder. calculate its energy when it reaches the ground? also calculate its velocity while it touches the ground (g=9.8m/s)
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Answer 1

Explanation:

Mass = 10 kg

Height = 5 m

so, by equation of position velocity relation

v² - u² = 2as

u = 0 m/s

a = g =10 m/s²

s = h = 5m

so, velocity just before hitting the ground = 10 m/s

and the kinetic energy = 1/2 mv² = 500 J