Solve the all parts of given question:
Question: A 0.4 kg ball is attached to a string of 0.75 m length and swung in such a way that its trajectory is a horizontal circle with a 0.15 m radius.
Part A: What is the tension in the string?
Part B: What is the period of motion?
Part C: Now imagine increasing the speed so that the tension and the radius increase. Determine how tension and the radius are related and plot FT vs. r.
Please show all intermediate steps and formulas.