Elevator An observer is 32 m above the ground oor of a large hotel atrium looking at a glassenclosed elevator shaft that is 28 m horizontally from the observer (see gure). The angle of elevation of the elevator is the angle that the observer's line of sight makes with the horizontal (it may be positive or negative). I Assuming that the elevator rises at a rate of 5 m/s, what is the rate of change of the angle of elevation when the elevator is 18 m above the ground? When the elevator is 60 m above the ground? Observer is: 28m Write an equation relating the angle, 6, and the vertical distance between the height of the elevator and the height of the observer, H. H tan6=E Differentiate both sides of the equation with respect to t. 1 de E dH dt sec 26 dt When the elevator is 18 m above the ground, the rate of change of the angle of elevation is D V (Type an exact answer in simplied form.)