Rick's next shot isn't as good. She hits the cue ball with a velocity of 5.6 m/s and it hits the 4 ball. The cue ball bounces off at a 45 degree angle off it's original path at a speed of 3.5 m/s. What is the velocity of the 4 ball?

Question

---So all i know is the momentum before is (.17)(5.6)=.952 kg*m/s.
Please help and thx!!

Answer 1

m₁=m₂=m=0.17 kg,
α=45°
v=5.6 m/s, v₁=3.5 m/s, v₂=?
vector p =vector p₁+vector p₂
p₂=sqrt{p₁²+p²-2p₁•p•cosα} =
=m•sqrt{3.5²+5.6²-2•3.5•5.6•cos45°} =
=m•3.99 ≈m•4 kg•m/s.
v₂ = 4 m/s