# Mechanics Question

1. Nov 19, 2007

### Varnson

1. The problem statement, all variables and given/known data
A particle slides under gravity along a smooth path in the x-z plane by z=b-(x^2/a).
Show that the energy of this motion can be expressed as E=.5m*xdot^2*[1+(2x/a)^2] + mgb[1-(x^2/ab)]

2. Relevant equations
T(A)+V(A) = T(B)+V(B), where T is kinetic energy

3. The attempt at a solution
I understand how to get the potential energy term, but I am confused on how to calculate the kinetic term.

2. Nov 21, 2007

### azatkgz

$$v^2=\dot z^2+\dot x^2$$

$$\dot z=-\frac{2x\dot x}{a}$$