19. Fluid Mechanics

A hollow aluminum sphere with outer diameter 10.0 cm has a mass of 690 g. What is the sphere's inner diameter?

If you tried to smuggle gold bricks by filling your backpack, whose dimensions are 54cm x 31 cm x 22 cm, what would its mass be?

(II) A bottle has a mass of 32.00 g when empty and 98.44 g when filled with water. When filled with another fluid, the mass is 89.22 g. What is the specific gravity of this other fluid?

The Earth is not a uniform sphere, but has regions of varying density. Consider a simple model of the Earth divided into three regions—inner core, outer core, and mantle. Let us assume each region has a constant density (the average density of that region in the real Earth). Use this model to predict the average density of the entire Earth.

On dry land, an athlete weighs 70.2 kg. The same athlete, when submerged in a swimming pool and hanging from a scale, has an “apparent weight” of 3.4 kg. Using Example 13–10 as a guide, What is the athlete’s percent body fat assuming it is given by the formula (495 / SG) - 450?

If the base of an insect’s leg has a radius of about 3.0 x 10^-5 m and the insect’s mass is 0.016 g, would you expect the six-legged insect to remain on top of the water? Why or why not?