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Question
If the speed of a car is halved, how does its kinetic energy change?
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Solution
K.E = `1/2 mv^2`
when `v_1 = 1/2 v`
∴ K.E. = `1/2 mv_1^2`
= `1/2 m (1/2 V)^2`
= `1/2 m v^2 (1/4)`
new K.E = `1/4 K.E`
∴ K.E changes to `1/4 th`
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