To find the velocity of the ball after it is hit by the cue stick, we can use the conservation of momentum principle. In this scenario, we will assume that the cue stick transfers some of its momentum to the ball.
Before the collision:
- Mass of the cue stick (\(m_1\)) = 0.5 kg
- Velocity of the cue stick (\(v_1\)) = 2.5 m/s
- Mass of the ball (\(m_2\)) = 0.2 kg
- Initial velocity of the ball (\(v_2\)) = 0 m/s (assuming it was at rest)
Calculating initial momentum:
The total initial momentum of the system is the momentum of the cue stick plus the momentum of the ball:
\[
\text{Total initial momentum} = m_1 v_1 + m_2 v_2
\]
\[
= (0.5 , \text{kg} \cdot 2.5 , \text{m/s}) + (0.2 , \text{kg} \cdot 0 , \text{m/s}) = 1.25 , \text{kg⋅m/s}
\]
After the collision:
Let \(v\) be the final velocity of the ball after being hit by the cue stick. The momentum of the system must be conserved, so we set the total initial momentum equal to the total final momentum.
The total final momentum is the momentum of the cue stick (which continues moving) and the momentum of the ball:
\[
\text{Total final momentum} = m_1 v_{1f} + m_2 v
\]
Here, \(v_{1f}\) is the final velocity of the cue stick after the collision. We don't have this value, but we can set up the equation focusing on the ball's momentum.
Assuming that after the collision the cue stick continues moving with a reduced speed, we don't need the exact value of \(v_{1f}\) to answer this question. Solving for \(v\) requires either additional information or making assumptions, such as whether the collision is elastic or not. Without loss of generality, let's assume an elastic collision, so that momentum conservation can be effectively applied.
Assuming the cue stick slows down a bit but still has some speed \(v_{1f}\), we can apply an assumption for simplified analysis - that the cue stick stops transferring the bulk of its speed to the ball and the ball gains the majority of the impact momentum.
Using just the cue stick's initial speed, one could say approximately:
\[
m_1 v_1 + m_2(0) = 0 + m_2 v
\]
Setting for maximum conservation impact:
\[
1.25 = 0 + (0.2)v
\]
Thus:
\[
v = \frac{1.25}{0.2} = 6.25 , \text{m/s} \approx 6.3 , \text{m/s}
\]
Therefore, the velocity of the ball after it is hit is approximately:
6.3 m/s.