When the sun is directly overhead, the thermal energy incident upon the earth is about 1.4 x 106 ergs- cm-2-sec-1. the diameter of the sun is about 1.6x 1011cm, and the distance from the sun to the earth is about 1.3 x 1013cm. assuming the that the sun radiates like a black body, use the expression to estimate its surface temperature.

Review multiple-concept example 7 in this chapter as an aid in solving this problem. in a fast-pitch softball game the pitcher is impressive to watch, as she delivers a pitch by rapidly whirling her arm around so that the ball in her hand moves in a circle. in one instance, the radius of the circle is 0.626 m. at one point on this circle, the ball has an angular acceleration of 66.1 rad/s2 and an angular speed of 12.6 rad/s. (a) find the magnitude of the total acceleration (centripetal plus tangential) of the ball. (b) determine the angle of the total acceleration relative to the radial direction.