Question

Some people think a pendulum with a period of 1.00 s can be driven with "mental energy" or psycho kinetically, because its period is the same as an average heartbeat. True or not, what is the length (in cm) of such a pendulum?

Answer 1

Answer:

l=24.8 cm

Explanation:

The period of a simple pendulum is given by

$T= 2\pi\sqrt{\frac{l}{g} }$

l= length of pendulum

g= acceleration due to gravity

taking square on both the sides we get

$T^2= 4\pi^2\frac{l}{g}$

This can be rewritten as

$l = \frac{T^2}{g}4\pi^2$

now substituting T= 1 and g= 9.8

$l = \frac{1^2}{9.8}4\pi^2$

l= 0.248 m = 24.8 cm