Momentum of ball bouncing off crossbar

[luffy3san]

Homework Statement

A soccer ball with a mass of 416 g bounces off the crossbar of a goal and is deflected upward at an angle of 56.7° with respect to horizontal. Immediately after the deflection, the kinetic energy of the ball is 46.9 J. What are the vertical and horizontal components of the ball's momentum immediately after striking the crossbar? (Let the horizontal direction be the x-direction and the vertical direction be the y-direction.)

Homework Equations

P = mv
KE = 1/2mv²

The Attempt at a Solution

KE_f = 0.5 * m * v²
46.9 = 0.5 * 0.416 * v²
v = 15 m/s

P = mv
Px = 0.416 kg * 15 m/s * cos 56.7 degrees = 3.43 kg m/s
Py = 0.416 kg * 15 m/s * sin 56.7 degrees = 5.22 kg m/s

Any help is appreciated. Thanks.

 

[mfb]

You should keep units everywhere, but I don't see where you need help.

 

[luffy3san]

You should keep units everywhere, but I don't see where you need help.

Ah sorry... I got those two values for the momentum, they were one of the options but was marked as wrong.

 

[haruspex]

I get the same answers as you - assuming the ball's not spinning.

 

[luffy3san]

I get the same answers as you - assuming the ball's not spinning.

Oh, thanks. We haven't covered angular momentum yet so shouldn't be... i think. I'll have to ask the instructor next class.