IIT JEE , AIEEE Forum - Physics , Mechanics

dilip

During vertical circular motion of a body, suppose a sphere tied to a string is revolved along vertical circle

then, why the tension along the string at the topmost point is zero?

please explain it in detail it's urgent.

LOOK DOWN THERE IS A DOUBT.

vagee

maybe it is balanced by the centrifugal force (against gravity)

sen_ayan

At the topmost point 2 forces are acting on the body. the weight force is acting vertically downwards and the centrifugal force due to its circular force is acting vertically upwards(centrifugal force always acts perpendicular to the velocity of the body.) when the two forces balance each other the tension acting on the body becomes zero.

mw^2r = mg( where m= mass of the sphere. w = angular velocity of the sphere r = radius of the vertical motion. g= accelaration due to gravity. )

rate me if you like it.

amrita

piku_siku

well its not always 0.000000000000000000000000000000000000
only when the centrifugal force=weight of the body T=0
if v=(rg)^1/2 =>t=0
v:velocity at the top most point

piku_siku

Also v=root(rg) is bare minimum velocity that should be given to the body to allow it to hav an circular motion...............

a_buddy4uin06

A simple logical explanation is tat if u hav some tension (which is always a pullin force) at the topmost point.. then the body wilol not b able to complete its motion, bcos the string will slag..

grbelli2020

at the highest positon tension becomes zero or grater becouse
at the highest point tension= weight - centrufugaforce if centrifugal
force and weight are equal tension becomes zero if centrifugal force is more tension becomes -ve so the string is in slagen it will not complete a vertical cricular motion

dilip

but grbelli isn't it that if centrifugal force becomes more the circular motion will get complete

grbelli2020

yes if centrifugal force is grater

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