Question

A 2.5 kg ball moving at 4.2 m/s collides with a 2.5 kg stationary ball. If the first ball is at rest after the collision, what is the velocity of the second ball? please solve the complete problem​

Answer 1

Answer:Question 2 O out of 3 points A 2.5 kg ball moving at 4.2 m/s collides with a 2.5 kg stationary ball in a perfectly elastic collision. What is the velocity of the second ball after the collision? Selected Answer: 4.2 m/s Answers: 4.2 m/s None of these 8.4 ms 1.2 m/s 4.8 m/s

Explanation:

Answer 2

Concept:

According to the law of conservation of momentum, in an isolated system, the total momentum of two or more bodies acting upon each other remains constant until an external force is applied to the bodies.

Given:

Mass of first ball, m₁ = 2.5 kg

The initial velocity of the first ball, u₁ = 4.2 m/s

The final velocity of the first ball, u₂ = 0 m/s

Mass of second ball, m₂ = 2.5 kg

The initial velocity of the second ball, v₁ = 0 m/s

Find:

The final velocity of the second ball.

Solution:

Let the final velocity of the second ball is v₂.

Applying the conservation of momentum,

m₁u₁ + m₂v₁ =m₁u₂ + m₂v₂

Substituting the given values,

m₁u₁ + m₂v₁ = m₁u₂ + m₂v₂

(2.5 × 4.2) + (2.5 × 0) = (2.5 × 0) + (2.5 × v₂)

(2.5 × 4.2) = (2.5 × v₂)

v₂ = (2.5 × 4.2) / (2.5)

v₂ = 4.2 m/s

Hence, the final velocity of the second ball is 4.2 m/s.

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