- #1

mjmontgo

- 10

- 0

## Homework Statement

In deep space a 7.0 kg rubber ball moving along the x-axis with a speed of 20 m/s collides ELASTICALLY with another ball of mass = 25 kg. After the collision the 7.0kg rubber ball's velocity is directed in the positive y axis. Find the final speed of the 7 kg ball, as well as the VELOCITY of the 25 kg ball (speed and direction)

## Homework Equations

m

_{1}v

_{1}= m

_{1}v

_{1f}+m

_{2}v

_{2f}

1/2m

_{1}v

_{1}

^{2}= 1/2m

_{1}v

_{1}

_{f}

^{2}+1/2m

_{2}v

_{2}

_{f}

^{2}

## The Attempt at a Solution

so i know that because the smaller mass is afterwards directed in the positive y direction, that all of its x momentum is transferred to the bigger mass. I've found a velocity for the x component of the bigger mass, however I am stucking finding the y component, which in turn would give me the over all final velocity, which i can use to calculate the angle as well as the final speed of the smaller mass. Would be greatly appreciated if someone could point out the extra equation I am missing. Basically what i have so far boils down to these equations:

m

_{1}v

_{1x}= m

_{2}v2

_{finalx}and i work out the x component of the larger mass to be 140/25 m/s

the other equation i have is for the y direction and that is :

-m

_{2}v

_{2fy}= m

_{1}v

_{1fy}

i know i somhow need to use the energy conservation formula but I am just not seeing it.

Thanks a lot in advance for you help and time guys.