All about Frames- The easy way...

4 Apr 2008

All about The Frames

Hi friends many of us face some difficulties in the concepts of frames, especially here we find many frame confusions?about pseudo forces and all?

Let me try to clear these?.hope so?.

Most of the info here is my own with some help from other sites,

Frames?..

Where we use this concept?

1) Not at one place?it has some different meanings at places.

2) We for IIT in mechanics have its relevance almost everywhere we use newtons laws of motion and other such laws of classical physics.

An important point which you find in kinematics and all is that,,,

Motion is relative..

The word ?relative? is so so important to understand?

TRY THIS AT HOME

(only under adult supervision..caution)

If you observe a ball thrown with some angle to horizontal and see it standing on the ground ..then you observe a parabola..hmmm?whats in that?ok..now you travel with a uniform speed ..you see it..still a parabola ..pata hai bhai ?.now you begin to run with an acceleration?.man?..i will not tell what you see?ok I tell ?you will not see a parabola..::J)))

Here is the relevance of frames?.i give you one hint here ..the rest and uniform velocity case is an inertial frame of REFERENCE and the later accelerated PART IS a non inertial frame?.hmmm?.

Zzz?.ok?.not so exciting?.let us try differently?

Invite your friend ?tell him to stand on a trolley..and another friend to drive it?give your ball?cricket ball..to him and say him throw it?

Now when the trolley is accelerated he will throw the ball..observe it?.YOU will NOT see a parabola (as you are a non inertial frame)?but your friend will see..( I hav some doubt over this part)?..

Now if possible you try to run with the acceleration of the trolley?..amazing.. it is a parabola??.

You must have got some hint now..

3) The important point is in case of newtons laws..

The Newtons` laws are applicable only in INERTIAL frames..and not in NON INERTIAL frames?.

Hmmm?so far so good..let us KnoW what the hell are inertial and non inertial frames?

4) INERTIAL FRAMES

They are the frames which are at rest or unaccelerated?

..you can apply newtons laws directly here??..no problem??..

5) nON INERTIAL FRAMES are the accelerated frames?.

To apply newtons laws here you got to apply the PSEUDO forces?.which are obtained by applying it equal and opposite to the acceleration vector?

..take this example?

In the down figure the pendulum box is in a non inertial frame accelerating towards right with a?to apply newtons laws ..take ?a acceleration on the body,,rightly speaking ma force opposite to direction of a?.

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