Problem
9. Two people are fighting over a Playstation 5 . One \( 100 \mathrm{~kg} \) customer eventually winds up at a speed of \( 10 \mathrm{~m} / \mathrm{s} \) on another \( 125 \mathrm{~kg} \) customer. What was the recoil velocity of the \( 125 \mathrm{~kg} \) customer? \( (8 \mathrm{~m} / \mathrm{s}) \)
Solution
Step 1 ：\( m_1 = 100 \mathrm{~kg} \)
Step 2 ：\( m_2 = 125 \mathrm{~kg} \)
Step 3 ：\( v_1 = 10 \mathrm{~m} / \mathrm{s} \)
Step 4 ：\( m_1 v_1 = m_2 v_2 \)
Step 5 ：\( v_2 = \frac{m_1 v_1}{m_2} \)
Step 6 ：\( v_2 = \frac{100 \times 10}{125} = 8 \mathrm{~m} / \mathrm{s} \)
