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Pseudo Force

November 9, 2019


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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