PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
Two identical steel spheres, A and B, each of mass 0.20kg, rest on a long horizontal air track that eliminates friction with the surface. Sphere A is launched with speed 2.0ms−1 toward stationary sphere B so that the spheres collide head-on along the track’s center line. Consider two extreme interaction cases: perfectly elastic and perfectly inelastic.
Unless otherwise directed, ignore external forces during the brief interaction.
(a) Describe qualitatively how linear momentum and kinetic energy are distributed between the two spheres immediately after a perfectly elastic collision.
(b) For a perfectly inelastic collision, the spheres stick together. Calculate the speed of the combined mass immediately after impact, then determine the percentage loss of the system’s kinetic energy during the collision.
(c) Explain where the mechanical energy that is "lost" in part (b) physically goes in a real laboratory setting. Identify at least two forms the energy may take and describe the mechanisms that produce them.
(d) Using your answers to the previous parts, discuss how total energy is conserved even though mechanical energy decreases in the inelastic case. In your explanation, reference the definition of the system boundary and energy transfers across that boundary.