Physics 2-D Momentum Homework Help

Question

I have a problem that I just can't figure out the answer for. Can anyone help me with it?

Question:

A 7.50 kg bowling ball moving 6.42 m/s strikes a 1.60 kg bowling pin at rest. After, the pin moves 14.8 m/s at a -47.0° angle. What is the x-component and y-component of the ball's final velocity?

Answer 1

Use the momentum balance (total momentum is conserved in any collision with no external net force on your system: the BB and P) in both x and y directions:

7.5 kg (6.42 m/s) cos(0°) = 7.5 kg(v_xBB) + (1.6 kg)(14.8 m/s) cos(-48°) x component of momentum

Do the same for y component with v_yBB and sines instead of cosines. .

Solve for v_x and v_y (Note you can just say 0 for the momentum in the y direction before the collision because the direction of the momentum is only in x. Of course, you get that when you plug in sin(0)