A rod of length `L` is suspended vertically from a point at a distance x from one end to oscillate under gravity. What should be `x` (approximately) so that it oscillates with minimum time period?

Options

A. 0.5 L
B. 0.2 L
C. 0.4 L
D. 0.3 L

Answer

B

Explanation

Time period will be minimum about a point at a distance K
(radius of gyration) from COM.
for rod `k=(L)/(2sqrt(3))~=0.29`L on either side of COM
From on end `0.5l +- 0.29=0.21L, 0.79L`
`~=0.2L,0.8L`