What can we say about the rock as it falls to earth? a) it accelerates as it falls. b) it falls at a constant rate of speed. c) it is at a constant velocity as it falls. d) it accelerates until it reaches a peak velocity, then decelerates.

Which statement is true if the refractive index of medium a is greater than that of medium b? a. total internal reflection is possible when light travels from air to medium b to medium a. b. total internal reflection is possible when light travels from medium a to medium b. c. total internal reflection is possible when light travels from medium b to medium a. d. total internal reflection is possible when light travels from air to medium a. e. total internal reflection is possible when light travels from air to medium b.