Question

A ball is fired at 5 m/s to the right and bounces off a second ball, initially at rest, and comes back to the left at 1m/s. What is the velocity of the second ball? Assume both balls have a mass of 3.86kg and make to the right positive.

Answer 1

6 m/s

Explanation:

Given:

Mass of balls (m) = 3.86 kg

Initial speed of ball 1 (u1) = 5 m/s

Final speed of ball 1 (v1) = - 1 m/s

Initial speed of ball 2 (u2) = 0 m/s

We make the balance for the moment and we are left with the following:

`\begin{gathered} m_1\cdot u_1+m_2\cdot u_2=m_1\cdot v_1+m_2\cdot v_2 \\ \\ \text{ We repalcing:} \\ \\ 3.86\cdot5+3.86\cdot0=3.86\cdot-1+3.86\cdot v_2 \\ \\ 19.3=-3.86+3.86v_2 \\ \\ 3.86v_2=19.3+3.86 \\ \\ v_2=(23.16)/(3.86) \\ \\ v_2=6\text{ m/s} \end{gathered}`

Therefore, the speed of the second ball is equal to 6 m/s