A hockey puck of mass slides on ice with an initial speed of
PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A hockey puck of mass 200g slides on ice with an initial speed of 12m/s. A second identical puck is gently placed on top of it so that the two stick together and move as one without any external horizontal force acting thereafter.
(i) Calculate the initial kinetic energy of the single puck.
(ii) After the second puck is added, find the common speed of the combined mass, assuming momentum is conserved during the sticking process.
(iii) Determine the kinetic energy of the combined system after they stick together.
(iv) Derive an expression for the percentage loss of kinetic energy when two identical bodies moving together after sticking are compared with the initial kinetic energy of one body. Verify your derivation with the numerical values obtained in parts (i)–(iii).