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Liono4ka [1.6K]
2 years ago
10

A ball is dropped from the top of a cliff. By the time it reaches the ground, all the energy in its gravitational potential ener

gy store has been transferred into its kinetic energy store. If the ball is travelling at 20 m/s when it hits the ground, what height was it dropped from? (Assume that the gravitational field strength is 10 N/kg.)
The answer is 20 meters, how do I get that?
Physics
1 answer:
gogolik [260]2 years ago
4 0

U = mgh, Ek = 1/2*m*v^2

U = Ek (conservation of mechanical energy)

⇒ mgh = 1/2*m*v^2

∵g = 10, v = 20

⇒ 10h = 1/2*400

⇒ h = 20 (m)

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