A35-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

given that

mass of stainless steel ball is

mass of other ball

speed of first ball before collision

speed of second ball before collision

after collision the speed of first ball is given as

Now it is given that there is no net force on the system of two balls

so here we will have

so here P = constant

which means initial total momentum of two balls must be same as final total momentum of two balls

so its correct option is 4.2 m/s

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.