Answer
given,
Tension of string is F
velocity is increased and the radius is not changed.
the string makes two complete revolutions every second
consider the centrifugal force acting on the stone
=
now centrifugal force is balanced by tension
T =
From the above expression we can clearly see that tension is directly proportional to velocity and inversely proportional to radius.
When radius is not changing velocity is increasing means tension will also increase in the string.
<span>Newton's Third Law of Action-Reaction is that for each and every action that happens, there is an equal and opposite reaction to it. In the scenario of a roller coaster, this is when you push down on the seat of the roller coaster as it flies along and the seat pushes back against you.</span>
I assume that the ball is stationary (v=0) at point B, so its total energy is just potential energy, and it is equal to 7.35 J.
At point A, all this energy has converted into kinetic energy, which is:

And since K=7.35 J, we can find the velocity, v:
I want to say that they will be primarily flat but I honestly don't know