In this video I’m going to teach you about

pseudo Force Pseudo means something that is fake

So why do we need to learn about something that is fake Remember!! laws of motion by Newton Let us revise them The first one was definition of inertia Second was the relation between force and momentum which in turn resolved to Force equals to mass into acceleration

And the last one action and reaction pair are equal and opposite Now we are very comfortable for using Newton’s laws of motion therefore in order to apply

Newton’s Laws accelerated frame of reference we must include a correcting Factor

Now why do you need correcting Factor For example

When you are travelling in a bus Because of the inertia the tendency of the

object to remain at rest unless an external forces act on it therefore we need a correcting

Factor Which is called as the pseudo Force

To explain this pulling effect Now for the mathematical part

Considered an inertial frame of reference denoted by S and an accelerated frame of reference

denoted by S’ which is accelerating towards the right side

with acceleration s’s consider an object of mass m in S’ on which an external Force F external is acting According to Newton’s Laws, external force will be equals to mass into acceleration ms Note that it is not equal to

Mass into acceleration ms’ Therefore acceleration of mass with respect

to s Will be equal to acceleration of mass in S’

Plus the acceleration of S’ itself simplifying it and multiplying Mass on both

sides we get Ma ms’ will be equal to ma ms minus ma S’S so our correcting factor final equation can be written as Ma ms’ will be equal to F external

Ma ms is nothing but F external ma S’S

hence in general we can say that pseudo force is the force acting in opposite direction

having acceleration of AFR w r t IFR Let us solve some examples

Mark the AFR and draw the pseudo force acting on m in the following cases

The first one Wagon accelerating towards right

First we mark the AFR The wagon itself is accelerating

So it becomes our AFR If the acceleration is a towards the right

side Then force will be equal to mass into acceleration

Here there is no external force acting on m

Hence the pseudo force will act towards the left side

And that will be equals to m into a In terms of magnitude Next is Elevator descending The elevator descending will have acceleration in the downward direction

Hence it is our AFR Therefore the pseudo force will act in the

upward direction of the magnitude ma The last one Wedge moves towards left

This entire wedge is accelerating towards left side

Hence it is our AFR Therefore a force will act on mass m

Towards the right side Equal to magnitude ma So now you get the general idea About AFR and pseudo force

And its magnitude Try this yourself

This block having masses m and m connected with a pulley and this entire block is accelerating

towards right Mark the AFR and label the forces acting on

these two smaller blocks Leave your answers on my Facebook page

Or you can tag me on Twitter Using #physicstutorials

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