Physics Two Dimensional Motion Question 86

Question: A 2 kgstone at the end of a string 1 m long is whirled in a vertical circle at a constant speed. The speed of the stone is 4 m/sec. The tension in the string will be 52 N, when the stone is

[AIIMS 1982]

Options:

A) At the top of the circle B) At the bottom of the circle C) Halfway down D) None of the above

Show Answer

Answer:

Correct Answer: B

Solution:

$ mg=20N $ and $ \frac{mv^{2}}{r}=\frac{2\times {{(4)}^{2}}}{1}=32N $ It is clear that 52 N tension will be at the bottom of the circle. Because we know that $ {T _{\text{Bottom}}}=mg+\frac{mv^{2}}{r} $