RRB Technician 2013 Ques 16
Question: Two bodies having masses in the ratio $ 2:3 $ fall freely under gravity from heights $ 9:16 $ . The ratio of their linear momenta on touching the ground is
Options:
A) $ 2:9 $
B) $ 3:16 $
C) $ 1:2 $
D) $ 3:2 $
Show Answer
Answer:
Correct Answer: C
Solution:
- Momentum = Mass $ \times $ Velocity =p $ v^{2}+u^{2}+2gh $ When $ u=0,,v^{2}=2gh $
$ \therefore $ $ v=\sqrt{2gh} $ $ \frac{p _1}{p _2}=\frac{m _1v _1}{m _2v _2}=( \frac{2}{3} )\frac{\sqrt{2gh _1}}{\sqrt{2gh _2}} $ $ =\frac{2}{3}\sqrt{\frac{h _1}{h _2}}=\frac{2}{3}\times \sqrt{\frac{9}{16}}=\frac{2}{3}\times \frac{3}{4}=\frac{1}{2} $
BETA
