The decay of 40K has a half of 1.3 × 10 9 years. The age of the earth is estimated at 4.6 × 10 9 years. The decay of 40K is a major heat source for the earth's interior. Relative to today, how much more heat was produced by 40K in the early Archaeon era or 3.9 × 10 9 years ago?

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.