Question

Two balls with masses of 0.4 kg and 0.6 kg respectively are thrown in such a manner that they collide head-on. They stick together and move with a common velocity. The initial velocity for each ball is 15 m/s. Calculate the velocity v.

a) 0 m/s
b) -3 m/s
c) 6 m/s
d) 9 m/s

Answer 1

The final velocity of the two masses after the collision is -3 m/s.

Step-by-step explanation:

When two objects collide and stick together, the law of conservation of momentum states that the total momentum before the collision is equal to the total momentum after the collision.

Mass A has a mass of 0.4 kg and an initial velocity of 15 m/s in the +x-direction. Mass B has a mass of 0.6 kg and an initial velocity of 15 m/s in the -x-direction. After the collision, the two masses stick together and move with a common velocity, which we'll call v. Since momentum is conserved, we can set up the equation:

mass A x initial velocity A + mass B x initial velocity B = (mass A + mass B) x final velocity

0.4 kg x 15 m/s + 0.6 kg x (-15 m/s) = (0.4 kg + 0.6 kg) x v

6 - 9 = v

Therefore, the common velocity of the two masses after the collision is -3 m/s. So the answer is b) -3 m/s.