Question 53

A ball is dropped from a height of 10 m.It strikes the ground and rebounds up to a height of 2.5 m. During the collision, the per cent loss in the kinetic energy is:

Solution

As per conservation of energy and momentum,

KEinitial = PEinitial=mghinitial

Similarly,

KEfinal = PEfinal = mghfinal

Percentage loss in KE = $$\frac{(mgh_{initial}-mgh_{final})}{mgh_{initial}}$$

= $$ \frac{h_{initial}-h_{final}}{h_{initial}}$$

= $$\frac{10-2.5}{ 10 }\times100$$

=75%

Option D is correct.


Create a FREE account and get:

  • Download RRB Study Material PDF
  • 45+ RRB previous papers with solutions PDF
  • 300+ Online RRB Tests for Free

cracku

Boost your Prep!

Download App