Which of these is the best explanation for why two negatively charged balloons, if put close, will repel?

What is the final velocity of the initial velocity of 25 and -50?

Carbon 14 is a naturally occurring stable

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.