Solving Momentum Homework Questions: Q1 & Q2

[Xtremeownage]

Homework Statement

Two Questions:

1) A 9.0-kg ball is traveling to the right at 8.0 m/s until it impacts a 3.0-kg stationary ball. After the collision, the 9.0-kg ball is traveling at 5.61 m/s at an angle of 7.8º above the horizontal. Calculate the velocity of the 3.0-kg ball after the impact. (Answer: 7.7m/s 17°S of E)

2) 3. A cue ball traveling at 0.785 m/s [270°] strikes a stationary five-ball, causing it to move at 0.601 m/s [230°]. The cue ball and the five-ball each have a mass of 160g. What will be the velocity of the cue ball immediately after impact? Ignore frictional and rotational effects. (Answer: 0.505 m/s @ 320°)

Homework Equations

p=mv

The Attempt at a Solution

They seem to be similar questions.

For question 1:

p = mv

p = (9) x (8) = 72 for ball 1

p = 0 for ball two

Impact momentum = (9) x (5.61) = 50.49 kg x m/s

Impulse = 72 - 50.49?

similar situation for question 2. What is the process for solving?

I have the answers, but how do you get to them?

Question 1: (Answer: 7.7m/s 17°S of E)

Question 2: (Answer: 0.505 m/s @ 320°)

 

[Doc Al]

Apply conservation of momentum. Hint: Since momentum is a vector, use a separate equation for each component.