(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Assume an elastic collision (ignoring friction and rotational motion).

A queue ball initially moving at 2.2 m/s strikes a stationary eight ball of the same size and mass. After the collision, the queue ball's final speed is 0.61 m/s.

Find the queue ball's angle [tex]\theta[/tex] with respect to its original line of motion. Answer in units of degrees.

2. Relevant equations

[tex]\frac{1}{2}mv_1_i^2+\frac{1}{2}mv_2_i^2=\frac{1}{2}mv_1_f^2+\frac{1}{2}mv_2_f^2[/tex]

3. The attempt at a solution

[tex]\frac{1}{2}mv_1_i^2+\frac{1}{2}mv_2_i^2=\frac{1}{2}mv_1_f^2+\frac{1}{2}mv_2_f^2[/tex]

[tex]v_1_i^2+v_2_i^2=v_1_f^2+v_2_f^2[/tex]

[tex]v_2_f=2.114 m/s[/tex]

From here I am unsure of how to come to the angle [tex]\theta[/tex] the question is asking for.

I thought it might be:

[tex]tan\theta=\frac{v_2_f}{v_1_i}[/tex]

This is incorrect, though.

Any guidance would be appreciated!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Angle of Queue Ball after elastic collision

**Physics Forums | Science Articles, Homework Help, Discussion**