Question

Please tell me How to find dimensions of physical quantities ...???

Answer 1

Which physical quantities?

Answer 2

Bro I don't know how to find any Dimension ..... tell me the proper method to find the dimensions .....

Answer 3

I don't fully uderstand what it is you're asking. But, if I had a physical object in front of me, like my cell phones let's say. The only way I could find the dimensions is by measuring them, like with a ruler.

Answer 4

That's not it . He wants to know how to find the Dimensions of the physical quantities like force acceleration.etc.

Answer 5

You can make a good start by looking at the units

For example Work is measured in J or Nm (Newton meters)

1 N = 1 kgm/s^2 (kg metre /second squared)

so 1 Nm = 1kg m^2 s^-2

kg , m and s are units of basic dimensions (mass, length time) so dimensions are M^2L^T^-2

Other quantities can be expressed in terms of the basic dimensions..

Answer 6

In the SI system, there are seven fundamental units: kilogram, meter, candela, second, ampere, kelvin, and mole.

Answer 7

The full method is known as Dimensional Analysis.

Whilst I have covered it - I don't fell competent to explain it...

Start here maybe..
http://en.wikipedia.org/wiki/Dimensional_analysis

Answer 8

CORRECTION....

You can make a good start by looking at the units

For example Work is measured in J or Nm (Newton meters)

1 N = 1 kgm/s^2 (kg metre /second squared)

so 1 Nm = 1kg m^2 s^-2

kg , m and s are units of basic dimensions (mass, length time) so dimensions are ML^2T^-2

Other quantities can be expressed in terms of the basic dimensions..

Answer 9

@MrNood please tell me the Dimensions of : Pressure and Density ....

Answer 10

Do what I did above

Start with the units Pressure is Nm^-2

It is very similar to what I did above for Work

Density is kgm^-3

Expand the units out until they are expressed in terms of basic dimensions

Answer 11

But please note - this method is not the full method you would need for an unknown property. The technique of Dimensional Analysis is the correct approach for these problems.
As I said above I have forgotten the details of how to do it. It is a powerful tool.

If you work through the 2 examples above you may begin to see how all (I think)properties can be expressed in terms of the basic dimensions.

Answer 12

Thank You so much .... I am very worried But Now I am fine ...

Answer 13

Do you want to do the above examples here - and show what you did?