By what factor should the length of the pendulum of a clock be changed if you want it to run 2 times faster?

The period of a simple pendulum is given by .

Here is the period, length of the pendulum and acceleration due to gravity. When the pendulum runs 2 times faster, the period gets halved. That is

. The new length of the pendulum is .

That is the length of the pendulum decreases by a factor of 4.

the answer would most likely be c, because if it's a comical piece of information, it may likely not be true, if it's a site that allows anybody to edit the content, it could mean a five year old is typing the info, and if it's a tv show produced by a celeb, it may have a biased opinion.

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.