Why are force fields necessary to describe electric force

What will a positive and a negative charge do if they are separated from each other?

An experiment was performed on a 2-kg block. forces of 5, 10 and 15 newtons respectively were applied to the block for 5 seconds. describe the difference in acceleration between the three trials. a) the final accelerations will all be the same. b) the final acceleration will triple between the first and third trial. c) the final acceleration will be cut by 1/3 from the first to third trial. d) the final acceleration will increase nine time between the first and third trial.

No matter what energy transformation we discuss, we know that no energy transfer is 100% efficient. you are about to enter a bicycle rave. you have trained extensively and eaten well to maximize your energy input throughout the bicycle race. you know that some of your kinetic energy will become wasted energy in the form of heat. what is the source of the heat energy and how can you minimize it to maximize the efficiency of your performance in the race? a) you are the source of the heat energy. you can minimize the heat energy but selecting the appropriate clothes to wear. b) air resistance is the source of he heat energy. you can minimize the air resistance by your position while riding the bicycle. c) friction is the source of the heat energy. you can minimize the friction by lubricating all appropriate parts and keeping the tires well inflated. d) kinetic energy is the source of the heat energy. you can reduce the production of heat energy but minimizing the energy you expend to race on the bicycle.