The seawolf class nuclear submarines have a crush depth of approximately d = 745 m. the density of seawater is ρ = 1.03×103 kg/m3. atmospheric pressure is p0 = 1.01×105 pa.
find the inward force of the water, in newtons, at crush depth on a circular porthole with a radius of r = 0.11 m.
if the interior of the submarine is kept at atmospheric pressure, what will be the magnitude of the net force on the porthole, in newtons?

You are the coordinator for a program that is going to take place at night in a rectangular amphitheater in the mountains. you will have no access to any electricity, but you must be able to illuminate the entire grounds. you know the intensity of the light from a lantern varies inversely as the square of the distance from the lantern. suppose the intensity is 90 when the distance is 5 m. a. write an equation to model the situation. b. solve for the constant of variation. c. write the equation to model the situation using the constant () of variation. d. you have been given lanterns with 40 light intensity. use your equation to solve for the distance from the lantern. e. you need to illuminate 225 km. how many meters do you need to light? f. how many lanterns will you need?