Deriving Newton's 2nd Law for Single Body in 1D Case

[astrozilla]

Homework Statement

How can Newton's 2nd law be derived for a single body in an 1Dimesional case ?

Homework Equations

F=m(du/dt)

The Attempt at a Solution

It is given that the principle of conservation of energy must be used,for the derivation.
Are there any more hints?

 

[kuruman]

No more hints are needed. Conservation of energy means that energy does not change with time, i.e. the rate of change of energy with respect to time is zero. Therefore ...