laktronics! help please !

[selpak]

why do we say
velocity = distance over time

why not
velocity = time over distance

or
velocity = time times distance



Added after 8 minutes:

my goal is to know how to put my own rule

Added after 1 hours 28 minutes:

what?
plz if it is silly just answer it...plz

 

[PR080]

Re: Help! I need elp!

Hi,


Velocity is nothing but rate of change of distance but not change of time with respect to distance.

Velocity is measured by caluculating how much distance covered with time.
That why we define velocity as a distance over time but not time over distance.

If it would time over distance it is meaningless .

 

[LouisSheffield]

Help! I need elp!

Consider "over" to imply division - time's in the denominator. A very useful way to memorize this (your rule?) is to consider the units ... m/s or meters per second ... the units mirror the underlying equation.

 

[laktronics]

Re: Help! I need elp!

Hi,
Strictly speaking one could have defined the way you have mentioned also. Velocity could have been defined as secs. per meter, meaning how many seconds it takes to cover one meter, or as a product of meter and time.
The basic concept, however followed is that we define variation of a dependent variable with respect to an independent variable. Here the independent variable is the time and the dependent variable is the displacement. So we define velocity as distance by time. Also the variable acceleration is rate of change of velocity, that is, change in velocity divided by time. If you adopted your way of definition, how to define acceleration?
Finally if you analyse, you will find that the time exists only as a concept introduced to quantify changes of variables. The variables would have changed whether the time changed or not, but we could not have quantified it, hence we had to borrow the concept of time.
It is always good to think different from others, then only you will get the real perspective of things, Eg., Newton and Apple.
with regards,
Laktronics

 

[selpak]

Help! I need elp!

thanx alot guyz ..
I`ll come back and read it deeply n carefully when I`m free..
thanx alots

 

[selpak]

laktronics
ummm...
I have a question
could there be motion without time( t = 0)? if not,then i guess the concept of limits is just all wrong? or what?
thank you

Added after 2 minutes:

Hi,


Velocity is nothing but rate of change of distance but not change of time with respect to distance.

Velocity is measured by caluculating how much distance covered with time.
That why we define velocity as a distance over time but not time over distance.

If it would time over distance it is meaningless .

meaningless, or just useless?

Added after 12 minutes:

Another thing is that, I actually understand that distance over time gives us how many meters have been passed in one second; but what i don`t understand is how does (division) does that( my problem, I guess, is with how division works).

 

[laktronics]

Hi,

could there be motion without time( t = 0)? if not,then i guess the concept of limits is just all wrong? or what?

Ofcourse, as I see motion has nothing to do with time. As I see everything in this universe changes state, and the only thing I do not perceive is time. Motion as I see is change of position, of a body, it will change its place whether your atomic clock is running or not. But if you want to study how fast an object moves, we need to bring in the concept of time, the unit of which has been taken based on the number of change of states of a stable repetitive vibration in nature. Otherwise what else is time?
Division comes into picture because, velocity is defined as displacement per unit time. So if displacement is 50 meters in 10 sec. the velocity is 50m÷10s = 5m/s.
Dimensions of all variables are arrived at using the individual dimensions of the component variables and the way they are computed. So we have the dimension of velocity as meters per sec.

Regards,
Laktronics