Is there a difference between potential difference, voltage and emf?

At a certain instant after jumping from the airplane a, a skydiver b is in the position shown and has reached a terminal (constant) speed vb = 52 m/s. the airplane has the same constant speed va = 52 m/s, and after a period of level flight is just beginning to follow the circular path shown of radius ρa = 2330 m. (a) determine the velocity and acceleration of the airplane relative to the skydiver. (b) determine the time rate of change of the speed vr of the airplane and the radius of curvature ρr of its path, both as observed by the nonrotating skydiver.

Four identical lab carts each have a mass of 200 kg. different masses are added to the carts and the velocities are measured. all carts move to the right.

To fully describe the photoelectric effect, scientists must consider which of the following to be quantized? o a. both light and matter o b. matter only o c. light only o d. neither light nor matter