A small ball is hung by a string from the ceiling of a train car, so that the ball hangs vertically. Moving from rest, the train car accelerates forward, and continues to accelerate. A team of scientists observes the behavior of the ball from various locations. From which scientist's frame of reference does the motion of the ball appear to violate Newton’s Law of Inertia? is it A on the Train station platform? B inside the train car? C in a second train car moving with constant speed in the same direction as the first train? Or D in a third train moving with constant speed opposite the direction of the first train?

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.

B) as the temperature increases, the kinetic energy of the particles increases.|-/