# Fun with Combining Eqations

1. Feb 14, 2005

### the_d

what is the process for combining 2 equations?

2. Feb 14, 2005

### dextercioby

What do you mean...??

Daniel.

3. Feb 14, 2005

### the_d

for example i have to combine These two equations for uniform circular motion and sole for T (the period of the motion)

Eq. 1 V = 2 pi(r) / T

Eq. 2 V^2 = (r / m)F

4. Feb 14, 2005

### dextercioby

The first one looks familiar,you may wanna explain what does the second represent...?

Daniel.

5. Feb 14, 2005

### the_d

the original equation is F = m(v^2 / r) but instead that one is solving for velocity squared when r and m are fixed but the question is asking me to combine the two equations and solve for the variable T (time for 1 revolution)

does any1 know how to combine them??

Last edited: Feb 14, 2005
6. Feb 14, 2005

### DaveC426913

Didn't you pick this up in High School?

Since the left side of an equation equals the right side...

- You have Eq 1 that sez v=...

- And Eq 2 that has a V in it. So substitute one for the other. Now you have one big equation. Then just rearrange it until you have T alone on the left.

7. Feb 14, 2005

### the_d

guess i must have been asleep for that lesson

8. Feb 14, 2005

### the_d

how do u divide a fraction by a fraction? is all u do flip the denominator with the numerator or is there more?

9. Feb 14, 2005

### dextercioby

No.Compute this:(8:4):(12:6)=...?

It's totally equivalent to:

$$\frac{\frac{8}{4}}{\frac{12}{6}}$$

Daniel.