30. For the graphs of g versus m shown below. (A) 1 - " V"V (D) # 1 (E) Which graph best represents the acceleration due to gravity g as a function of mass m, near the surface of the earth? 31. Which graph shown below, (A) F- " K" (D) (E) best represents the magnitude of the centripetal force F as a function of the speed v for an object moving in a fixed circular path? 32. The position-time graph of an object moving due north is a straight line with a positive slope. This means that the object has a (a) constant displacement. (b) steadily increasing acceleration. (c) steadily decreasing acceleration. (d) constant velocity. (e) steadily increasing velocity.33. 34. A car accelerates from rest down a straight road. A short time later the car stops and backs up to the starting point. Which one ofthe following position-time graphs best illustrates the motion of the car? no g is? it: (Bl r. r, E D f- to} E 0 t In the photoelectric effect, increasing the frequency of the light incident on a metal surface (a) decreases the threshold frequency for the emission of photoelectrons (b) decreases the number of photoelectrons emitted (c) increases the threshold frequency for the emission of photoelectrons (d) increases the kinetic energy of the most energetic photoelectrons (e) does not affect the kinetic energy of the photoelectrons