Work Energy And Power Question 303
Question: Two identical balls A and B are released from the positions shown in figure. They collide elastically on horizontal portion $ M/N $ . All surfaces are smooth. The ratio of heights attained by A and B after collision will be
Options:
A) $ 1:4 $
B) $ 2:1 $
C) $ 4:13 $
D) $ 2:5 $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] After collision, balls exchange their velocities
$ \therefore $ $ V _{A}=\sqrt{2gh} $
and $ V _{B}=\sqrt{2g(4h)}=2\sqrt{2gh} $
Height gained by A will be $ h _{A}=h $
But path of B will be first straight line and then parabolic as shown in figure
After calculation, we can show that $ h _{B}=\frac{13}{4}h $
$ \therefore $ $ \frac{h _{A}}{h _{B}}=\frac{4}{13} $
