Question

A smooth sphere $A$ of mass $0.1kg$ is moving with speed $5m/s$ when it collides head on with another smooth stationary sphere of same radius. If $A$ is brought to rest by the impact and $e=\frac{1}{2}$, then,

• A. speed of B just after impact is $2.5m/s$
• B. the mass of $B$ is $0.2kg$
• C. magnitude of impulse during collision is $0.5Ns$
• D. the mass of $B$ is $0.4kg$

Answer 1

Answer: (A), (B), (C)

speed of B just after impact is $2.5m/s$
the mass of $B$ is $0.2kg$
magnitude of impulse during collision is $0.5Ns$

At first B was at rest and finally A was at rest an e is given as $0.5$
so vel. of B after collision $=$ 1/2(vel. of A initially) $=2.5m/s$
momentum will be conserved ,so $5\ast 0.1=2.5\ast mm=0.2Kg$
impulse$=5\ast 0.1-5\ast 0=0.5Ns$