Question

If momentum of a body is decreased by 50%, then
kinetic energy will be decreased by
[NCERT Pg. 119]
2
(1) 25%
(2) 50%
(3) 75%
(4) 125%
​

Answer 1

Answer:

Let the initial momentum be P

i

=P

Final momentum P

f

=1.5P

Initial kinetic energy K.E

i

=

2m

p

2

Final kinetic energy K.E

f

=

2m

p

f

2

=

2m

(1.5P)

2

=2.25K.E

i

Percentage increase in kinetic energy

K.E

i

K.E

f

−K.E

i

×100=

1

2.25−1

×100=125 %