Physics Two Dimensional Motion Question 84

Question: A 1 kg stone at the end of 1 m long string is whirled in a vertical circle at constant speed of 4 m/sec. The tension in the string is 6 N, when the stone is at (g = 10 m/sec2)

[AIIMS 1982]

Options:

A) Top of the circle B) Bottom of the circle C) Half way down D)None of the above

Show Answer

Answer:

Correct Answer: A

Solution:

$ mg=1\times 10=10N, $

$ \frac{mv^{2}}{r}=\frac{1\times {{(4)}^{2}}}{1}=16 $ Tension at the top of circle = $ \frac{mv^{2}}{r}-mg=6N $ Tension at the bottom of circle = $ \frac{mv^{2}}{r}+mg=26N $