While deriving the expression for kinetic energy, the displacement is written as s=2av2−u2. Substituting this into W=Fs and using F=ma, which intermediate expression is obtained before any further simplification?
a) W=m(v2−u2)
b) W=2m(v−u)2
c) W=ma(2av2−u2)
d) W=21m(v2−u2)