Kinematics Question 532
Question: A block of mass $ m $ at the end of a string is whirled round in a vertical circle of radius $ R $ . The critical speed of the block at the top of it’s swing below which the string would slacken before the block reaches the top it’s [DCE 1999, 2001]
Options:
A) $ Rg $
B) $ {{(Rg)}^{2}} $
C) $ R/g $
D) $ \sqrt{Rg} $
Show Answer
Answer:
Correct Answer: D
Solution:
At highest point $ \frac{mv^{2}}{R}=mg $
therefore $ v=\sqrt{gR} $
