What force causes the periodic motion of a pendulum?

O

A. Gravity

O

O

O

B. Elastic force

C. Nuclear force

D. Electric force

the Answer is A

Explanation:

because the swinging motion of a pendulum is due to the force of gravity generated by the earth's size

the answer of this question is option A because,

Pendulum. If you swing a weight on a string, it will go back and forth in regularperiodic motion ... The force of gravitycauses the pendulum bob to change directions, while the force from the string moves it in a semi-circular motion