A ball of mass 2 kg is dropped from the top of a building of height 20 m. Calculate the mechanical energy of the ball and kinetic energy of the ball when it reaches the ground.
Take g = 10 ms $^{- 2}$

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Solution

Given : Mass (m) = 2 kg; Height (h) = m ; initial velocity (u) = 0 m/s
Solution : Mechanical energy at top of cliff = Potential energy at at top of cliff ( Since KE at top = 0 )
=> ME at top = PE at top = mgh = 2 x 10 x 20 = 400 J

Now, Mechanical Energy at bottom = KE at bottom = PE at top = 400 J( Mechanical energy remains conserved )

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A ball of mass 2 kg is dropped from the top of a building of height 20 m. Calculate the mechanical energy of the ball and kinetic energy of the ball when it reaches the ground. Take g = 10 ms−2

A ball of mass 2 kg is dropped from the top of a building of height 20 m. Calculate the mechanical energy of the ball and kinetic energy of the ball when it reaches the ground.
Take g = 10 ms $^{- 2}$