Which of the following colors are part of the visible spectrum?
A. violet
B. blue
C. red
D. all of these

Which of the following describe possible scenarios? a) an object has zero instantaneous velocity and non-zero acceleration. b) an object has negative acceleration and is speeding up. c) an object has positive acceleration and constant velocity. d) an object has positive velocity and zero acceleration. e) an object has increasing positive position and negative velocity. f) an object has decreasing positive position and negative acceleration.