Question: A stone is tied to a string and whirled in a vertical circle of radius 1 m. What is the minimum speed at the top of the circle to keep the stone in circular motion?
Options:
Correct Answer: 2 m/s
Solution:
At the top, centripetal force = weight. mv²/r = mg. v² = rg. v = √(1*9.8) ≈ 3.13 m/s.