Two billiard balls, each with a mass of 0.17 kg, collide with each other on a pool table. Before the collision, one ball is moving south at 2.8 m/s and the
other ball is moving north at 1.6 m/s. What is the momentum of this system
after the collision?
A. 0.20 kg. m/s north
B. 0.20 kg m/s south
C. 0.60 kg m/s south
D. 0.60 kg: m/s north

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.