4. A certain part of an aircraft engine has a volume of 1.4 ft³.

(a) Find the weight of the piece when it is made of lead. (b) If the same piece is made of aluminum, what is its weight? (C Determine how much weight is saved by using aluminum instead of lead.

5. The depth of the Pacific Ocean in the Mariana Trench is 36,198 ft. What is the gauge pressure at this depth?

6. A storage tank 31 m high is filled with pure water. (Assume the tank is open and exposed to the atmosphere at the top.)

(a) Find the gauge pressure at the bottom of the tank. (b) Calculate the magnitude of the force produced by the fluid that acts on a square access hatch at the bottom of the tank that measures 0.7 m by 0.7 m