Question

Two billiard balls each of mass 0.05 kg moving in opposite directions with speed 6 m s¯¹, collide and rebound with the same speed. What is the impulse imparted to each ball due to the other ?

Answer 1

Given: The mass of each ball is 0.05 kg and the magnitude of speed of each ball is 6 ms -1 .

Initial momentum of each ball is given as,

p i =mv

Where, m is the mass of each ball and v is the velocity of each ball.

By substituting the given values in the above expression, we get

p i =mv =0.05×6 =0.3  kgms −1

After collision, the balls change their directions of motion without changing the magnitudes of their velocity.

Final momentum of each ball is given as,

p f =− p i

By substituting the given values in the above expression, we get

p f =−0.3  kgms −1

Impulse imparted to each ball is given as,

I=Δp = p f − p i

By substituting the given values in the above expression, we get

I=−0.3−0.3 =−0.6  kgms −1

The negative sign indicates that the impulses imparted to the balls are opposite in direction.

Thus, the impulse imparted to each ball is −0.6  kgms −1 .