show that for a single particle with constant mass the equation of motion implies the following differential equation for the kinetic energy

dT/dt=F.v

Aparticle moves in the X-Y plane under the constraint that its velocity vecter is always directed towards a point on the X axis whose abscissa is some given function of time F(t) .show that for F(t)differentiable, but otherwise arbitrary,the constraint is nonholonomic