p
posted by Sam .
A certain string can withstand a maximum tension of 41 N without breaking. A child ties a 0.35 kg stone to one end and, holding the other end, whirls the stone in a vertical circle of radius 0.91 m, slowly increasing the speed until the string breaks.
(a) Where is the stone on its path when the string breaks?
a)at a random point on the path
b)cannot be determined
c)at the lowest point on the path
d)at the highest point on the path
(b) What is the speed of the stone as the string breaks?
m/s

Abbreviating the subject as "p" is not helpful to teachers looking for questions in their area of expertise.
The string will break where the stress is highest. At the bottom of the vertical loop, the string tension T must balance both weight and centripetal forces.
T = M [(V^2/R) + g]
At the top,
T = M [(V^2/R)  g]