Dropping a rock from 4 feet in the air is an example of what type of energy?

Asmall object with mass 0.200 kg swings back and forth on the lower end of a light rope that is 3.00 m long. the upper end of the rope is attached to the ceiling. as the object swings through its lowest position, where the rope is vertical, the speed of the object is 5.80 m/s. at this point in the motion, what is the tension in the rope? (use g = 9.80 m/s2.)

Explain why electric current cannot exist if a current doesn't have a voltage source.

What is the coefficient of kinetic friction μk between the block and the tabletop?