Question

Ball 1 (1.5 kg) moves to the right at 2 m/s and ball 2
(2.5 kg) moves to the left at 1.5 m/s. The balls stick together after collision. What is the speed and direction of ball 2 after the collision?

Answer 1

Answer:

0.1875 m/s leftward

Explanation:

Taking rightwards as positive

We are given:

Ball 1:

Mass (m1) = 1.5 kg

velocity (u1) = 2 m/s

Ball 2:

Mass (m2) = 2.5 kg

velocity (u2) = -1.5 m/s          [negative because it is in the opposite direction]

Speed and Direction of Ball 2:

We are told that the balls stick together after the collision

We can say that the balls have the same velocity since they are sticking together

So, Final velocity of Ball 1 (v1) = Final velocity of Ball 2 (v2) = V m/s

According to the law of conservation of momentum

m1u1 + m2u2 = m1v1 + m2v2

replacing the variables

1.5(2) + (2.5)(-1.5) = V (1.5 + 2.5)                     [v1 = v2 = V]

3 + (-3.75) = 4V

-0.75 = 4V

V = -0.75/4                                                    [dividing both sides by 4]

V = -0.1875 m/s

Hence, the balls will move at a velocity of 0.1875 m/s in the Leftward direction