# Week 17

Topics: Archimedes' principle; Hydrostatic pressure; Pascal's principle; Bernoulli's law

Lab: Buoyancy and archimedes' principle.

Homework Problems: Due on Monday, Dec. 11 at noon.

1. Ice cube: A large ice cube, whose density is 0.917 g/cc, is placed in a glass. Water is then poured into the glass until the glass is full to the rim.
• First, what fraction of the ice cube is submerged? (Solution: 91.7 percent)
• When the ice melts, will the water level overflow the glass, will it fall below the rim, or will it remain the same? Explain your answer. (Solution: it would remain at the same level. Suppose the ice cube had a volume of 1 cc. 0.917 cc was below water. When it melts, the new volume will be 0.917 cc, since its density increased by just this much.)
• Hydraulics: A fluid-filled syringe has a plunger with a diameter of 1 cm. The needle has a diameter of 1 mm. The plunger is depressed at a rate of 1 cm per second.
• With what speed will the fluid squirt from the tip of the needle? (Since the cross-sectional area of the needle is 1/100 that of the plunger, the speed will be 100 times as great. So the fluid squirts out at 100 cm/second.)
• If the end of the needle is capped, and a force of 1 pound is applied to the plunger, what force will be applied to the end cap? Explain your answer. (By pascal's principle, the force will be 1/100 of a pound)

Quiz: Next week covering fluid statics and dynamics

Gallery of Fluid Motion
General College Physics