a car of mass 500kg is moving 24 m/s. a lion of mass 100kg drops on to the roof of the car from an overhanging branch. show that the car will slow down to 24m/s.

Answer 1

There is no external horizontal force on the lion/automobile system.
Therefore the total horizontal momentum of the system will not change.
before:
500 * 24 + 100 * 0 = 12,000
after:
(500 + 100) v = 600 v
so
600 v = 12,000
6 v = 120
v = 20 m/s (not 24 of course)

Answer 2

before momentum :-
24*500=12000
after momentum:-