A hot air balloon rises at a constant speed of 13 meters/second relative to the air. There is a wind blowing eastwards at a speed of 0.7 meters/second relative to the ground. What is the magnitude and direction of the balloon's velocity relative to the ground? Use the Pythagorean
theorem to verify the answer.

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.