A CONCEPT ON TORQUE ,CENTER OF MASS ,CENTER OF GRAVITY AND COUPLE ALONG WITH APPLICATIONS .
INTRODUCTION -All the masses of an object are assumed to be concentrated in the center of mass of that object. Center of gravity of the object is a point on which the resultant of gravitational forces acts .In most of the cases the position of the center of gravity and the center of mass are the same but it is not true for all objects .
When a force is applied to the center of mass or center of gravity of an object, that is, the object does not rotate, but if the force is applied to a point other than the center of mass, the object rotates. | Torque is the cause of rotation as a result of the application of force to an object = | r × F |, where F is the applied force and r is the perpendicular distance from the center of mass of the object to the line along which the force is being applied. Now if force is applied to the center of mass then the value of r will be zero so the value of torque applied to the object will be zero, so that the object will only have translational movement but no rotation.
APPLICATION IN DAY TO DAY LIFE -
If we put a book on the table by keeping it flat then the book will be stable position and if we perturbed the book then the book will not fall but if we keep the book perpendicularly to the plane of the floor or table then the center of gravity of the book will be higher so the book will be unstable and with a little perturbation the book will fall on the floor .See the picture below .
When we open the cap of a bottle then we actually apply two equal quality forces parallel and opposite to each other with our two fingers so that the cap can be opened or closed. What we do here is we apply force with our fingers. Now these two opposite forces are called couple. So with the help of this couple we open the bottle cap. Now if we apply the force very gently with the help of the finger, then we will see that the cap is not opening because the required couple has not been formed, so if you apply it with a little more force, the cap will open nicely because the required couple is obtained. Now i hope you understood the process to open the bottle cap.
We can remember a short poem to understand the center of gravity -
“In the center of gravity the weight of the object is centralized
Many of us are aware of this
Added with mathematics
Applied to solve the problem of balances .
As low as the center of gravity of the object will be
The more stable the object would be “
References-
1.www.britannica.com/science/centre-of-gravity.
2.http://physicsnet.co.uk/a-level-physics-as-a2/mechanics/moments/
the writing was originally published in “SCIENTIPHILIA” (Bengali) on 29 th AUGUST ,2020.
ACKNOWLEDGEMENT -
I GREATLY ACKNOWLEDGE MY RESPECTFUL TEACHERS and MY PARENTS FOR GIVING FULL SUPPORT .ALSO THANKS TO MY FRIEND SOUMYADIP MOITRA FOR ASSISTING ME .
