If the speed of a body is halved ,what will be the change in its kinetic energy??????????

plz answer

too easy one....

as we knw that

K.E1 = 1/2 m v12

if the speed is halfed ...then.

let the new kinetic energy be K.E2

and its new velocity ( v2) = v1/2

K.E2 = 1/2 m v22

K.E2  = 1/2 m( v1 / 2)2  ( since  v2 = v1 / 2 )

  = 1/2  m  ( v12 / 4 )

  = 1/2  (m v12 )  1 / 4

  = 1/4 [  1/2 ( m v12 )]  ( since  K.E1  = 1/2 mv12 )

K.E2  = 1/4 K.E1

Hence , the new kinetic energy must be 1 / 4th of the previous kinetic energy.

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