A particle P of mass m lies on a smooth inclined plane at an angle a to the horizontal, where tanα = 3/4 The particle is attached to one end of a light elastic string of natural length a and modulus of elasticity 3 mg. The other end of the string is attached to a fixed point O on the plane. The particle P is in equilibrium at the point A on the plane and the extension of the string is 2a/5.
The particle is now projected from A down a line of the greatest slope of the plane with speed V. It comes to an instantaneous rest after moving a distance 1a/5.
By using the principle of conservation of energy,
a) Find V in terms of a and g (6 marks) ( so far for this question I've tried to make the initial energy of the particle equal to the final energy of the particle, so I've made the E.P.E (initial)+ K.E(initial) +G.P.E(initial)= E.P.E (final)- i thought that there would only be E.P.E as it's at rest and i assume that you make the GPE equal to zero) Any help will be appreciated!