Practice question
Question
A 9kg mass at 15m/s collides elastically with an identical stationary mass. What is the speed of the first mass after collision?
Explanation
For elastic collision, momentum and kinetic energy conserved: m1v1+m2v2=m1v1'+m2v2' and ½m1v1²+... per NCERT. Solving gives velocities matching 0 m/s. Inelastic loses energy. So option A is correct.