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

Object A has a mass of 2.0 kg and an initial velocity of 2.5 m/s. It strikes Object B, which is at rest and has a mass of 2.0 kg as well.

After the collision, the objects travel in different directions, with Object B travelling at an angle of 44 degrees from its original position.

What is the velocity of Object B after the collision and what is the displacement angle of Object A from the point of collision?

2. Relevant equations

Momentum before collision = momentum after collision

P_{x}= (m_{1}* v_{f1}* cosX) + (m_{2}* v_{f2}* cosY)

P_{y}= (m_{1}* v_{f1}* sinX) + (m_{2}* v_{f2}* sinY)

KE before collision = KE after collision

KE_{f}= (.5)(m_{1})_{vf1}^{2}+ (.5)(m_{2})_{vf2}^{2}

3. The attempt at a solution

I first calculated the components of momentum and kinetic energy before impact.

P_{x}= 2 kg * 2.5 m/s = 5.0 kg*m/s

P_{y}= 0 kg*m/s

KE = .5 * 2 kg * 2.5 m/s = 6.25 J

Then, I setup equations relating the objects post-impact to the momentum and energy they should have.

5 = 2*vf1*cosX + 2*vf2*cos44

0 = 2*vf1*sinX + 2*vf2*sin44

6.25 = v_{f1}^{2}+ v_{f2}^{2}

I've tried using substitution to solve for one of the variables, but each time I end up getting arcsines within cosines equaling sines. And I really don't know how to solve from there.

Am I at least on the right track? Should I solve for the angle first? Does it matter?

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: 2D Conservation of Momentum

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