- #1

Foghorn

- 8

- 0

## Homework Statement

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?

## Homework 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}

## 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?