Periodic motion can BEST be defined as motion

A) in three dimensions.
B) along a curved path.
C) repeated in intervals of time.
D) in a circle at a constant speed.

Sorry i don’t know what to do

Answeroutward from: source;

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.

Ithink c because you have to work to become goid