If the speed of a ball increased from 1m/s to 4m/s, by how much would the kinetic energy increase

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.)

Aphase diagram assumes is kept constant.

You have 80 g of 60oc water and 80 g or 10oc water. what is the final temperature when the two are mixed? explain.