A ball of mass 1kg moving with a velocity of 15m`//`s undergoes a head on elastic collision with another ball of unknown mass at rest, and rebound with a velocity of `10m//s`. What is the mass of the other ball?

Explanation

To solve the problem, we will use the principles of conservation of momentum and the properties of elastic collisions. Here are the steps to find the mass of the other ball:

### Step 1: Understand the Problem
We have a ball of mass \( m_1 = 1 \, \text{kg} \) moving with a velocity \( u_1 = 15 \, \text{m/s} \) that collides elastically with another ball of unknown mass \( m_2 \) which is initially at rest (\( u_2 = 0 \)). After the collision, the first ball rebounds with a velocity \( v_1 = -10 \, \text{m/s} \) (negative because it is in the opposite direction).

### Step 2: Apply Conservation of Momentum
The law of conservation of momentum states that the total momentum before the collision is equal to the total momentum after the collision.

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