Three small identical steel balls A,B and C are suspended by vertical threads of equal length from a horizontal support, with centres in a horizontal line and separated by a small gap. A is raised by a height 'h', with the thread taut, and released. All subsequent collisions are elastic.
(i) When all the balls have mass 'M', determine the subsequent motion of the system and the height to which the centre of C is raised following its first collision.
(ii) When A has mass 'M', B has mass '2M' and C has mass '3M', determine the height to which the centre of C is raised after its collision.
The Attempt at a Solution
This is an additional question that my Physics teacher gave me. I know PE=KE needs to be used here but I am not even getting close to a reasonable answer for (i) or (ii).