Question

identical balls each of mass 4 kg are moving towards each other with speeds 2 mls and 3 m/s
respectively. They undergo head on perfectly elastic collision. Then impulse imparted by one ball on other is
(1) 12 Ns
(2) 8 Ns
(3) 20 Ns
(4) 40 Ns​

Answer 1

Answer:

Impulse is given as Force × Time

Force = Mass × Acceleration

Acceleration = ( v - u ) / Time  

Where, v and u are final and initial velocities respectively.

⇒ Impulse = Mass × ( v - u ) / Time × Time

Time gets cancelled and we get,

⇒ Impulse = Mass × ( v - u )

According to the question,

Mass = 4kg

v = 3 m/s

u = 2m/s

⇒ Impulse = 4 ( 3 - ( - 2 ) )   [ Because Velocity of 2m/s is opposite ]

⇒ Impulse = 4 ( 5 ) = 20 N.s

Therefore option c is correct.

Hope it helped !!

Answer 2

$\huge\bf\underline\blue{Solution\: is\: attached\:here.}$

$\huge{\underline{\green{\boxed{Answer:- \:(3)\: 20 Ns}}}}$