Q. An observer, whose eyes are 1.77 m above the ground, is standing 28.0 m away from a tree. The ground is level, and the tree is growing perpendicular to it. The observer's line of sight with the treetop makes an angle of 22.0° above the horizontal. How tall is the tree?
Q. In a skating stunt known as "crack-the-whip," a number of skaters hold hands and form a straight line. They try to skate so that the line rotates about the skater at one end, who acts as the pivot. The skater farthest out has a mass of 65.0 kg and is 4.10 m from the pivot. He is skating at a speed of 7.00 m/s. Determine the magnitude of the centripetal force that acts on him.