Question

1. A plastic ball of mass 300g moves with a velocity of 34 cm/s. This

plastic ball collides with a second plastic ball of mass 200 g which is
moving along the same line with a velocity of 15cm/s. After the
collision, the velocity of the 200 g mass is 36 cm/s along the same
line. What is the velocity of the 300 g mass?

Answer 1

We can use the law of conservation of momentum to solve this problem. According to this law, the total momentum of the system before the collision is equal to the total momentum of the system after the collision.

Let's define the positive direction to be the direction of motion of the 300g ball before the collision. Then the initial momentum of the system is:

p1 = m1 * v1 + m2 * v2

where m1 and v1 are the mass and velocity of the 300g ball, and m2 and v2 are the mass and velocity of the 200g ball, respectively.

Substituting the given values, we get:

p1 = (0.3 kg) * (34 cm/s) + (0.2 kg) * (15 cm/s)

p1 = 12.9 kg cm/s

After the collision, the 200g ball moves with a velocity of 36 cm/s. Let's call the final velocity of the 300g ball v3. Then the final momentum of the system is:

p2 = m1 * v3 + m2 * 36 cm/s

Substituting the given values, we get:

p2 = (0.3 kg) * v3 + (0.2 kg) * (36 cm/s)

p2 = 0.3 kg v3 + 7.2 kg cm/s

Since the total momentum of the system is conserved, we have:

p1 = p2

Substituting the values, we get:

12.9 kg cm/s = 0.3 kg v3 + 7.2 kg cm/s

Solving for v3, we get:

v3 = (12.9 kg cm/s - 7.2 kg cm/s) / 0.3 kg

v3 = 18 cm/s

Therefore, the velocity of the 300g mass after the collision is 18 cm/s.

Step-by-step explanation: