Physics - Center of Mass Question with Solution | TestHub
In a carom-board game the striker and the coins are identical and of mass m. In a particular hit the coin is hit when it is placed close to the edge of the board as shown in figure such that the coin travels parallel to the edge. If the striker is moving with speed V before the strike, then the net impulse on the striker during collision if it moves perpendicular to the edge is (assume all collisions to be perfectly elastic)
Options:
Answer:
Solution:
In an elastic collision with a stationary identical coin, the coin leaves along the line of centres. Since the coin travels parallel to the edge, the line of centres at impact is vertical (parallel to the edge). The striker's velocity V at 45 degrees splits into V/sqrt(2) along the line of centres, which is transferred to the coin, and V/sqrt(2) perpendicular to the edge, which the striker retains. So the coin imparts an impulse mV/sqrt(2) on the striker along the line of centres. The striker then moves perpendicular to the edge straight into the wall and bounces back elastically, so the wall delivers an impulse 2 x mV/sqrt(2) = sqrt(2) mV on the striker, perpendicular to the first impulse. Net impulse on the striker = mV sqrt( (1/sqrt(2))^2 + (sqrt(2))^2 ) = mV sqrt(5/2). Answer: (A).
