Q3 of 13 Page 128

Answer the following

A ball of mass 200g falls from a height of 5m. What is its kinetic energy when it just reaches the ground?(g = 9.8 ms-2)

Given: Height = 5m.


Mass = 200g = 0.2 kg


g = 9.8ms-2


Formula used: Potential energy = mgh


⇒ Potential Energy = 0.2 kg × 5m × 9.8 ms-2


= 9.8 J


When the ball is present at the 5m height it possesses potential energy, which is equal to kinetic energy possessed by the ball when it just reaches the ground.


∴ K.E energy will be = 9.8 J


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