When we view the sun's disk in visible light, we see less deeply into the sun near the limb than at the center of the disk because of interaction of the light with atoms of gas. What conclusion can be drawn from the observation that the sun appears less bright near the limb than it does at the disk center?

If a rock is thrown upward on the planet mars with a velocity of 10 mys, its height in meters t seconds later is given by y − 10t 2 1.86t 2 . (a) find the average velocity over the given time intervals: (i) [1, 2] (ii) [1, 1.5] (iii) [1, 1.1] (iv) [1, 1.01] (v) [1, 1.001] (b) estimate the instantaneous velocity when t − 1.