A block moving horizontally on a smooth surface with a speed of 20 m/s bursts into two equal parts continuing in the same direction. If one of the parts moves at 30 m/s, with what speed does the second part move and what is the fractional change in the kinetic energy?

Explanation

To solve the problem step by step, we will follow these steps:

### Step 1: Define the initial conditions
Let the initial mass of the block be \(2m\) and its initial velocity be \(v_i = 20 \, \text{m/s}\). After bursting, the block splits into two equal parts, each with mass \(m\). Let the velocities of the two parts be \(v_1\) and \(v_2\), where we are given \(v_1 = 30 \, \text{m/s}\).

### Step 2: Apply the principle of conservation of momentum
According to the conservation of momentum, the total momentum before the burst must equal the total momentum after the burst.

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