Question

Suppose that you hit a billiard ball and give it an initial velocity of 1.6 m/s.This billiard hits a stationary ball which gains a speed of 1.2 m/s. What is thefinal speed of the first ball? (Assume that this is an elastic collision andthat the mass of each ball is 0.20kg)

Answer 1

Given:

The mass of each ball, m=0.20 kg

The initial velocity of the first ball, u=1.6 m/s

The velocity of the stationary ball after the collision, v₂=1.2 m/s

To find:

The speed of the first ball after the collision.

Step-by-step explanation:

From the law of conservation of momentum, the total momentum of a system always remains the same.

Thus,

`\begin{gathered} mu=mv_1+mv_2 \\ \Rightarrow u=v_1+v_2 \end{gathered}`

Where v₁ is the velocity of the 1st ball.

On substituting the known values,

`\begin{gathered} 1.6=v_1+1.2 \\ \Rightarrow v_1=1.6-1.2 \\ =0.4\text{ m/s} \end{gathered}`

Final answer:

The speed of the 1st ball aft