Point A is on the ground, and points B and C are h = 20 meters above the ground. Point B
is directly above point A, and point C is L =
45 meters away from point A as shown.
How much work must be done by an external
agent to move a 5 kg object from rest at point A to
rest at point B?
(b) How much work must be done to move the same
object from rest at point A to rest at point C?

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.