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Question
A body of 2 kg falls from rest. What will be its kinetic energy during the fall at the end of 2 s? (Assume g = 10 m/s2)
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Solution
Mass of the body, (m) = 2 kg
Initial velocity of the ball, (u) = 0 m/s
Time, (t) = 2s
Acceleration due to gravity, (g) = 10 m/s2
Let the final velocity of the ball after 2 s be (v)
We know v = u + at
So, v = 0 + 10 (2) = 20 m/s
Now we can find the kinetic energy as:
Therefore,
`K.E = 1/2 (2)(20)^2 "J"`
= 400 J
So, the kinetic energy of the moving object is 400 J.
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