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

l=24.8 cm

Step-by-step explanation:

The period of a simple pendulum is given by

`T= 2\pi\sqrt{(l)/(g) }`

l= length of pendulum

g= acceleration due to gravity

taking square on both the sides we get

`T^2= 4\pi^2(l)/(g)`

This can be rewritten as

`l = (T^2)/(g)4\pi^2`

now substituting T= 1 and g= 9.8

`l = (1^2)/(9.8)4\pi^2`

l= 0.248 m = 24.8 cm