Question

prove that change in kinetic energy is equal to work done

Answer 1

Formula of kinetic energy is 1/2mv²
we have to derived the equation of kinetic energy.
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taking the the thirds equation of motion, v²=u²+2as.
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v²=0+2as
v²=2as
taking the 'a' equal to f/m.
v²=2×f/m×s.
v²=2×f×s/m
f×s=m/2v²
work done =1/2mv².proved

Answer 2

work=fscostheta
kinetic energy= 1/2mv^2
let initial kinetic energy be ki ad final kinetic energy be kf
so change in kinetic energy is kf -ki
1/2mv^2. -1/2mv^2
so take common then answer will come