a particle (C) of mass m = 0.2 kg can slide without friction on an inclined plane making an angle alfa (a) = 30 degrees with respect to the horizontal (aka ground) . (C) is launched at at an instant to=0 along a line Ox of greatest slope with an initial velocity of Vo =5 m/s . thus , (C) moves along Ox. At any instant t , the position of (C) is given by its abscissa x=OA. the horizontal plane passing through O is the reference level for the gravitational potential.

Question

a) calculate the mechanical energy of the system {(C) earth.
b) express in terms of x the gravitational potential energy of the system {(C) earth}