Answer:
15.10m/s
Step-by-step explanation:
The mass of the ball(m)=400g = 0.4kg
The radius of the string is(r)=15m
The tension in the string is(T)=10N
The acceleration due to gravity =

The tension in the string when the body is at the bottom is given by

To find the speed of the ball, we make v the subject of the formula
Therefore,




The speed of the ball = 15.10m/s