# Help me subtract V1 from M1*V1/M1+M2

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#### The74namesofgod

##### Junior Member level 3 ok this should be easy but i cant figure it out im trying to
subtract V1 from M1*V1/M1+M2 and the ancer is (M2/M1+M2)*V1 so how do i get from the problem to the ancer thanks

in other words im trying to subtract V1 from V center of mass

#### jcy

##### Junior Member level 3 Re: help with equation

Are you sure you typed your equations correctly? The first equation

M1*V1/M1 + M2

reduces immediately to V1+M2 since the M1's cancel.

#### saeidj

##### Member level 2 Re: help with equation

Hi
I think you should use parentheses in the correct places.
V1 - M1*V1/(M1+M2) = [1 - M1/(M1+M2)]*V1 = [M2/(M1+M2)]*V1
Best

#### The74namesofgod

##### Junior Member level 3 Re: help with equation

yes im sure. that is why i dont get it

#### Element_115 Re: help with equation

What is the original equation?
1) [ (M1*V1)/(M1+M2)]
or
2) [ (M1*V1)/M1]+M2

Sol 1) [ (M1*V1)/(M1+M2)] - V1 --> (V1{M1-1})/(M1+M2)-->
--------> {V1*M1/(M1+M2)} - {1*V1/(M1+M2)}

Sol 2) {(M1*V1)/M1}+M2 - M1 --> (V1+M2-M1)

I just saw that this is a Mass Velocity problem. Can you write an equation that
relates M1/V1 to M2/V2 ? I think you need to introduce a new equation to get the
Cheers
Hope this helps

#### The74namesofgod

##### Junior Member level 3 #### faiflay

##### Member level 1 Re: help with equation

this the step of solution of the equation

### The74namesofgod

Points: 2

#### The74namesofgod

##### Junior Member level 3 Re: help with equation

thanks!!!!!!!

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