Class 11 Physics | Elasticity | #19 Elongation of Suspended Rod Under Self Weight | For JEE & NEET

[@RukdSG]

Thank you for this video. It was difficult for me to agree on the formula without derivation on my book. Now it is clear

[@shwetasinha2506]

Are you an IITian now?

[@Professor_Ray]

HEY WHERE ARE YOU NOW

[@_kshitij_j_]

WE NEED ANSWERS

[@harshsingh22105]

@@shwetasinha2506 wbu?

[@harshsingh22105]

@@Professor_Ray wbu?

[@devanshgupta3473]

Sir if rod is placed in lift with acceleration g downwards then their will be no elongation?

[@physicsgalaxyworld]

yes... you are right...

[@ArvindSingh-dy4lh]

Devansh G how?

[@kartikrana1641]

@@ArvindSingh-dy4lh Pseudo Acceleration On Rod Will be Upwards Net Acceleration Will be Zero So Effective Weight of Rod Will be Zero So No Tension Will be Produced And Body Will Not Stretch As No Force is on Body

[@jugalshah9261]

Sir in the elemental dx part, there is also a stress due to the upward mass which is compressing the dx part, so why didn’t we take it into account

[@harshsingh22105]

X is to much small part it will not experience any stress

[@kartikgkalita]

​bro thats a really good point

[@mohaksharma7658]

Respected Sir, I am stuck on a question for quite a long time...If we are given with a rod with its dimensions and Young's modulus which is free to move on a smooth surface...Then how to find the elongation in rod if a constant force F is applied on it?

[@physicsgalaxyworld]

+Mohak Sharma Use acceleration of rod a=F/m then consider an element of width dx at a distance x from one end of rod and find the tension in this element using T=(mass of rod behind this element)x(acceleration) then stress =T/S and strain =dy/dx as dy we consider elongation in element of length dx then integrate dy for the whole length of rod to get the total elongation...

[@mohaksharma7658]

Physics Galaxy Thanks a lot Sir..I got the ans..FL/2AY.. Thank u once again.

[@sanjughosh4826]

sir, is it working on non uniform application??

[@physicsgalaxyworld]

what do you mean by non uniform applications...

[@ujjwalchitransh6411]

Sir can we apply centre of mas concept to get ans?

[@physicsgalaxyworld]

As elongation varies with the distance from the suspension point... center of mass cannot be used in this case...

[@SumaidSyed]

Sir,we know that fractional change in the transverse length is proportional to fractional change in longitudinal length,so area of cross section is also changing,so how can we use that equation?

[@physicsgalaxyworld]

+Syed Sumaid As the cross sectional area of the wire is very small, we neglect the change in this analysis... even if you include the effect will be very small in case of numerical analysis...

[@SumaidSyed]

Thank you very much!

[@MessiEnic_]

Awaj sunke cry aagya

[@smileeverytime1684]

Sir how M/L*x*g is coming????? PL tell sir please

[@mohamednouman227]

Why are we integrating if the force is constant?

[@ownbrace9131]

Force is mass dependent... It's not constant

[@RohanKUMAR-tf6pp]

Sir please tension bata dijeye mx/l kaise aaya

[@namanmishra771]

Thanks a lot sir 👍🎉🎉

[@IITiann]

same question appeared in jee mains 2020

[@devanshgupta3473]

Sir if force is acting inside the rod(not on the surface) then any effect is their on the dimension of rod ? And we consider that force for stress formula or not?

[@physicsgalaxyworld]

here we consider force is distributed uniformly over any cross section of the rod... it is used in stress analysis...

[@adityaranjan6871]

Jhakas sir ....

[@harshmaurya5966]

sir what will be the enery stored by self elongation (plz help )

[@gautam9339513131]

Thx a lot

[@suhanajamwal8217]

Thnx sir

[@besidevlogs8098]

Watching in 2023 ......😊..

[@adityasart2644]

Ol

[@akashiseijuro4444]

or you can simply take the length L as L/2 from centre of gravity

[@arbinndo4620_IIT]

Sir why is strain = dy/dx?

[@physicsgalaxyworld]

because in elemental length dx we are considering a deformation dy so strain is given as ratio of deformation to initial length...

[@raphaelapologetics4499]

Ok

[@SumaidSyed]

How does the diameter of rod vary from top to bottom after elongation?

[@physicsgalaxyworld]

+Syed Sumaid This you can find by using the elongation in every element dx and by keeping the volume constant... here we neglect the slight change in the average separation between molecules... Even if you do not wish to neglect this... you can use bulk modulus of the material to calculate this... but this will be a long analysis...

[@SumaidSyed]

Thanks you for explanation.

[@manvisinghkrishnpremi1206]

Right now..... u must be in foreign 🤣

[@nirajkrn]

​@@manvisinghkrishnpremi1206haha sahi m yaar

[@kunalnarwal2753]

Itna purana concept 😂 8 years ago.....

[@arbinndo4620_IIT]

thank you sir.

[@refrainrestrainresist-3rs49]

Thank you so much sir!