Work Energy And Power Question 80
Question: Two solid rubber balls A and B having masses 200 and 400 gm respectively are moving in opposite directions with velocity of A equal to 0.3 m/s. After collision the two balls come to rest, then the velocity of B is [CPMT 1978, 86, 88]
Options:
A) 0.15 m/sec
B) 1.5 m/sec
C) ? 0.15 m/sec
D) None of the above
Show Answer
Answer:
Correct Answer: C
Solution:
Initial linear momentum of system = $ m _{A}{{\vec{v}} _{A}}+m _{B}{{\vec{v}} _{B}} $ = 0.2 × 0.3 + 0.4 × vB Finally both balls come to rest
final linear momentum = 0
By the law of conservation of linear momenum
0.2 × 0.3 + 0.4 × vB = 0 $ v _{B}=-\frac{0.2\times 0.3}{0.4}=-0.15\ m/s $
