# Simplifying math homework help

1. Dec 27, 2009

### gold123456th

1. The problem statement, all variables and given/known data
Show how to simplify (mBvB2 - mBvC2 - mCvC2)/(mBvB2) to mC/(mC + mB)

2. Relevant equations
vB is not equal to vC.
vB = muzzle speed of a bullet = unknown value
vC = speed of the clay block after it is hit by the bullet = unknown value
vB = ((2gh)0.5(mB + mC))/mB
vC = (2gh)0.5
g = gravitational acceleration
h = unkown height
mB is not equal to mC
mB is the mass of a bullet. mB is unkown though
mC is the mass of a clay block. mC is also unkown

3. The attempt at a solution
I have tried many different methods, but I still cannot show how to simplify the above equation

Last edited: Dec 27, 2009
2. Dec 27, 2009

### sylas

Re: Simplifying

You need more equations showing some relationships between your variables. If the variables are uninterpreted, the equation doesn't hold. For example, suppose vB = vC. In this case the equation on the left reduces to -mC/mB, which is only matches the right hand side when mC = 0 or mC = -2mB.

Cheers -- sylas

3. Dec 27, 2009

### gold123456th

Re: Simplifying

I just edited the thread. Hope all the info are there

4. Dec 27, 2009

### sylas

Re: Simplifying

Yes. Can you cancel out the variables you don't need? That is, g and h?

5. Dec 27, 2009

### gold123456th

Re: Simplifying

Yeah of course