Ahot air balloon is on the ground, 200 feet from an observer. the pilot decides to ascend at 100 ft/min. how fast is the angle of elevation changing when the balloon is at an altitude of 2500 feet?

If you were to drop a rock from a tall building, assuming that it had not yet hit the ground, and neglecting air resistance. what is its vertical displacement (in m) after 6 s?

Athin plate moves between two parallel, horizontal, stationary flat surfaces at a constant velocity of v = 7.5 m/s. the two stationary surfaces are spaced 4 cm apart, and the medium between them is filled with oil whose viscosity is 0.9 n·s/m2. the part of the plate immersed in oil at any given time is 2 m long and 0.5 m wide. if the plate moves through the mid-plane between the surfaces, determine the force required to maintain this motion. what would your response be if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top surface (h1)? if the plate moves through the mid-plane between the surfaces, the force required to maintain the motion will be n. if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top (h1) surface, the force required to maintain the motion would be n.

Unpolarized light whose intensity is 1.19 w/ is incident on a polarizer. (a) what is the intensity of the light leaving the polarizer? (b) if the analyzer is set at an angle of = 41.0∘ with respect to the polarizer, what is the intensity of the light that reaches the photocell?