When we calculate the min velocity at the bottom a body can have while moving in vertical circle attached to a string of length r we calculate the min value of vel for which T=0 and get v=√5gr
but when we calculate the same for a body attached to a light rod.. we calculate the min valu when v=0 at top and get v=√4gr
plz explain y we do so...
1when the velocity is zero for a body attached to a string the body will undergo freefall as the string will become loose (since T=0) so the only force acting is mg downwards.
33because...
when attached to string... if we take v=0 at top.. then T becomes zero.. before reaching top.. so it follows parabolic path afterwards.. so circle is not completed...
When attached to rod.. T can become zero before reaching top but then also it will complete circle... because rod is rigid... So we can take v=0 at top..
106free fall from the point where T=0 will give a parabolic path...
13the tension of rod need not necesarily become zero...as it can support the weight
but in case of string as it can't support the tension needs to be zero to complete the circle
33It has some velocity component in horizontal as well as vertical direction.. when T becomes zero....
106T can become zero before reaching top but then also it will complete circle... because rod is rigid...
can u explain that priyam .. how?? (it can complete the circle)
33@ abhirup.. for v=0 at top.. T necessarily becomes zero in between...
U can find the theta for that..
33tension becomes zero... (then negative...) for rod...
But if velocity is non zero.... what will be the path of ball when connected to rod... it will be circle only... till there is some velocity...
13@ Priyam
i actually meant.....
the tension of rod need not necesarily become zero at the top for minimum velocity