Answer:
Tension = 60 N
Explanation:
The ball is executing a motion like a pendulum. The lowest point of a pendulum's motion is the mean position, where its potential energy becomes zero and kinetic energy becomes maximum. At this point the rope becomes straight vertical. Hence, the tension in the rope becomes exactly equal to the weight of the object at the lowest point. Also, in this case when the ball swings through the lowest point during its motion like a pendulum, the tension in the rope will become equal to the weight of the ball.
Tension = Weight
Tension = 60 N
