Why do proportional formulas need a constant?

[mphr]

why should there is a 'constant' in a formula in which charactors on both sides are propotional to each other? and what should be the importance of it?

 

[neutrino]

Two quantities are said to be proportional when their ratio is a constant. If some variable y is proportional to another variable x, then their ratio, y/x, is a contant.

y/x = k => y = kx. (k is some constant)

 

[TuviaDaCat]

why should there is a 'constant' in a formula in which charactors on both sides are propotional to each other? and what should be the importance of it?

im not sure that i understood ur question...
are u asking what role constants play in physical equations?

because is u do, my answer is that those constants are there to keep all physical equations in the same unit system...

lets take the niotonic equation on the gravitational force:
F=GMm/r^2
this equation in principle is the same as : F=Mm/r^2.

though such formation of the equation, will not give us the force in Newtonic units, so we cannot compare this force to other known foces other than gravity...

i hope i was clear though my crippled skills in english...

 

[rbj]

lets take the niotonic equation on the gravitational force:
F=GMm/r^2
this equation in principle is the same as : F=Mm/r^2.

though such formation of the equation, will not give us the force in Newtonic units, so we cannot compare this force to other known foces other than gravity...

you can define units that get rid of these constants of proportionality. these are often called "natural units". check out:

http://en.wikipedia.org/wiki/Natural_units

and take your pick of which constants to lose.

 

[TuviaDaCat]

you can define units that get rid of these constants of proportionality. these are often called "natural units". check out:

http://en.wikipedia.org/wiki/Natural_units

and take your pick of which constants to lose.

it does not contradict with what i said.
all i said that constants are there to keep a all physical properties in a certain system of units.

ofcours u may use those "natural units", after all the Newton unit was defined by multiplying our earthly gravity with mass.

but u cannot compare two forces from different equalities of a property.
if there is nothing to say, just say nothing, I am annoyed that u just spill words without relating to what i wrote, maybe its because I am tierd... no matter...