Students designed an experiment to determine how a force exerted on a system does work on that system as it moves through a displacement. In this case, the force is provided by the hanging mass m2 and the displacement is the vertical distance h indicated on the diagram. The mass of the string and the friction in the pulley are negligible, but there is a non-negligible force of friction Fk between m1 and the table. Assume that the system does move when released, and that the speed upon hitting the floor is v. Which of the following is a correct relationship between the quantities involved in the experiment? (A) m2gh=12m1v2
(B) m2gh-Fkh=12m1v2
(C) m2gh-Fkh=12(m1+m2)v2
(D) m2gh=12(m1+m2)v2

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.

100 pounds is 100 pounds no matter the object or item being weighed