Alight elastic string has natural length 0.4 m and spring constant is 122.5 n/m. a particle p of mass 0.3 kg is attached to one end of the string. the other end of the string is attached to a fixed point a on a ceiling. the particle is released from rest a vertically. the particle first comes to instantaneous rest at the point b. (10 marks) (a) find the distance ab (b) the particle is now held at the point 0.6 m vertically below a and released from rest. find the speed of p immediately before it hits the ceiling