A 35-gram stainless steel ball on a track is moving at a velocity of 9 m/s. On the same track, a 75-gram stainless steel ball is moving at a velocity of - 7 m/s. After colliding, the 35-gram ball moves at a velocity of - 15 m/s. Assume there is no net force on the system. What is the velocity of the 75-gram ball after the collision? Round to the nearest tenth. - 4.2 m/s - 0.5 m/s 0.5 m/s 4.2 m/s

Option D is the correct answer.

Explanation:

The given figure shows the arrangement

We have momentum is conserved before and after collision.

Momentum before collision

= 35 * 9 + 75 * (-7) = - 210 g m/s

Momentum after collision

= 35 * (-15) + 75 * V = 75 V - 525

V is the velocity of 75 g ball after collision.

We have momentum conservation equation

So, - 210 = 75 V - 525

75 V = 525 - 210 = 315

V = 4.2 m/s

So velocity of 75 g ball is 4.2 m/s.

Option D is the correct answer.