Impulse and final velocity of billiard balls after collision

[pebbles]

Homework Statement

A billiard ball going 4 m/s collides with a stationary ball of equal size cause the second ball to move at an angle of 35 degrees at speed of 2.5 m/s
--mass=.3 kg
What impulse (magnitude and direction) did second ball receive? What about the first ball?
What is the final velocity (magnitude and direction) of the frist ball?

Homework Equations

impulse=kg * m/s
final velocity...?

The Attempt at a Solution

Impulse of second ball=.3*2.5= .75 kg*m/s
Impulse of first ball=.3*4=1.2 kg*m/s
Those right? How do I calculate the direction...?

 

[TMM]

You can make life a little easier for yourself by keeping the vector definitions of the initial momenta. Then when you finish, direction will be incorporated into your answer, you'd just need to find the magnitude.

 

[Shooting Star]

Billiard balls are assumed to be perfectly elastic.

What quantities are conserved in elastic collisions?

 

[pebbles]

shooting star-kinetic and momenta

 

[Shooting Star]

Then why don't you equate the initial and final energies and momenta rpty?

Resolve the final momenta in the two directions along and perp to the initial direction of the first ball.