1. ## Momentum collision problem

Two 72.0 kg hockey players skating at 5.45 m/s collide and stick together. If the angle between their initial directions was 115 $^{o}$, what is their speed after the collision?

$p_{ix} = p_{fx} = 0$

$p_{iy} = p_{fy}$

$m_{A}v_{A} + m_{B}v_{B} = (m_{AB})(v_{AB})$

$(72)(5.45cos(32.5)) + (72)(5.45cos(32.5)) = 144v_{AB}$

$v_{AB} = 4.60 m/s$

Am I correct?

2. You're using the wrong angle... You need to use cos(57.5) instead... The adjacent sides you're solving for get canceled out.