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Question
Obtain an expression for the kinetic energy of a body of mass m moving with a velocity v?
Solution
Let the body is brought to rest by a retarding force F after traveling a distance s.
From relation v2 = u2 + 2aS, retardation a =`"v"^2/(2"S")`
∴ Retarding force F = ma `="m"xx"v"^2/(2"S") =1/2("mv"^2) /"S"`
Work done W = F × S `=1/2("mv"^2)/"S"xx"S"=1/2"mv"^2`
Hence K.E = `1/2` mv2
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