# Homework Help: Pool balls grade 12

1. May 27, 2007

### hassan123456

pool balls grade 12 plz help

issue resolved tyvm to Trajan22

Last edited: May 28, 2007
2. May 27, 2007

### hassan123456

i know this is asking quite a bit but its very apreciated

3. May 27, 2007

### trajan22

What have you done so far?

4. May 27, 2007

### hassan123456

gotten confused beyond beileif and reileized the book doesnt include a suitable example, this is beacause the example totally exludes angles.

5. May 27, 2007

### trajan22

Well I am going to assume two things so tell me if I am wrong. The mass of both balls are the same and that you know the equation for momentum.

The way you start this problem and all problems like it is to break this up into components, find the sum of the momentums in the x direction and then find another equation for the sum of the momentums in the y direction.

Last edited: May 27, 2007
6. May 28, 2007

### hassan123456

yes the mass is the same and would i be using the right formula (numbers are supposed to be subscript) if im using: M1V1+M2V2=M1V'1+M2V'2

edit: one problem i have no idea how to discern the x and y direction am i right in saying that i should try using pascals triangle or something?

Last edited: May 28, 2007
7. May 28, 2007

### trajan22

The equation you are using is right but you will end up with two equations.
The mass is the same no matter which direction so all you are concerned with is the velocity which moves with different x and y components depending on the angle. So just use sin's and cos's to find these components.
So since the first ball is traveling horizontally initially its y component is zero. However it deflects at an angle to where the velocity has both an x and y component to it.

One more question is the 41.5% in the answer supposed to be 41.5 degrees

8. May 28, 2007

### hassan123456

yes it is sorry about that

ok now you lost me how do i use the sin and cos
ps: im really thankfull that your spending your time

Last edited: May 28, 2007
9. May 28, 2007

### trajan22

Well here is a general form of the equation.
$$M_{1}V_{1x}+M_{2}V_{2x}=M_{1}V'_{1x}+M_{2}V'_{2x}$$
and another equation for the y components
$$M_{1}V_{1y}+M_{2}V_{2y}=M_{1}V'_{1y}+M_{2}V'_{2y}$$
but in the problem they give you an angle that the first ball deflects at being 29.7 degrees below the x axis so in order to find the x component you would simply have a Vcos(theta) to be the x component of the ball. Where V is the velocity the ball is traveling and theta is the angle. Its easiest to think about it like a triangle with the hypoteneuse going in the direction the ball is traveling and the x and y components being the opposite and adjacent sides.

10. May 28, 2007

### hassan123456

thank you so much lol if only you were my teacher instead. you have no idea how gratefull i am right now. again thank you so much

11. May 28, 2007

### trajan22

No problem, if you have any other questions just ask.

12. May 28, 2007

### hassan123456

will do i even bookmarked this site and sent emails to my friends about how they should us it if need be

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