Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A body falling from a height of $10 \mathrm{~m}$ rebounds from hard floor. If it loses $20 \%$ energy in the impact, then coefficient of restitution is
PhysicsCenter of Mass Momentum and CollisionJEE Main
Options:
  • A 0.89
  • B 0.56
  • C 0.23
  • D 0.18
Solution:
2688 Upvotes Verified Answer
The correct answer is: 0.89
As \(20 \%\) energy lost in collision therefore \(\mathrm{mgh}_2=80 \%\) of \(\mathrm{mgh}_1 \Rightarrow \frac{\mathrm{h}_2}{\mathrm{~h}_1}=0.8\)
Here \(h \propto v^2\)
and \(e=\frac{v_f}{v_i}\)
so in such cases:
\(\mathrm{e}=\sqrt{\frac{\mathrm{h}_2}{\mathrm{~h}_1}}=\sqrt{0.8}=0.89\)

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.