Rebecca jogs in place for two minutes before her track meet. rebecca weighs 100 pounds. which of the following statements is true?
a rebecca has done 200 foot-pounds of work.
b rebecca has not done work because she has not moved a distance.
c rebecca would accelerate more quickly is she weighed 120 pounds.
d rebecca has done 100 foot-pounds of work.

The answer is A because it was 2 minutes and she weighs 100 lbs so 2(100)=200 200 lbs of work

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.