Question

The speed of a body revolving in a vertical circle of radius T at the lowest point is (5gr)^1/2. The tension in the string at the upper most position will be
0 mg
O 3 mg
O 5 mg
O Zero​

Answer 1

$\huge\star{\underline{\mathtt{\red{A}\pink{N}\green{S}\blue{W}\purple{E}\orange{R}}}}⋆$

Applying WET between A and B.

2m(2gR)2+mg(2R)=2mv02

mgr+2mgR=2mv02

v0= √6gr

Answer 2

Answer:

answer:6mg

Explanation:

Radius =R ,tension=T

at lowermost point T+mg=mv^2/r & at highest point T-mg=mv^2/r.

Here given V=√5gr,

we need the tension T at the uppermost position therefore,

T-mg=mv^2/r

T-mg=m×5gr/r = 5mg

T=mg+5mg=6mg

T=6mg