PhysicsFluids

Homework Ms. Heininger

1. (a) What is a fluid?

(b) What is the difference between liquids and gases? Explain with examples.

2. Define density. Define mass density. Write the formula for mass density. The following table

gives some useful formalae to determine the volume for various shapes.

Figure Volume

Rectangular Box l × b× h

Cube l3

Cylinder πr2h

Sphere 43πr

3

(a) A cube of side 1.2 m has a mass of 1500 kg. Determine the density of the cube.

(b) A sphere of radius 0.5 m has a mass of 1200 kg. Determine the density of the sphere.

(c) A cylinder of radius 25 cm and height 75 cm weighs 1000 N . Determine the density ofthe sphere.

(d) The density of mercury is 1.36×104 kg/m3. What is the mass of a 2.00×10−4 m3 sampleof mercury?

(e) What mass of water (at 4.00 C) can be contained in a rectangular box whose dimensionsare 8.0 cm by 5.00 cm by 2.00 cm? The density of water at 4.0 0C is 1.000 × 103 kg/m3.

(f) The density of iron is 7860 kg/m3. What is the mass of an iron sphere whose diameter is0.25 m?

(g) At standard temperature and pressure, carbon dioxide has a density of 1.98 kg/m3. Whatvolume does 1 kg of carbon dioxide occupy at standard temperature and pressure?

(h) Within a certain type of star called a neutron star, the material at the center has a massdensity of 1.0× 1018 kg/m3. If a small sphere of this material of radius 1.0× 10−5 m weresomehow transported to the surface of the earth, what would be the weight of this sphere?

(i) A solid cylinder has a radius of 0.051 m and a height of 0.0030 m. The cylinder is composedof two different materials with mass densities of 1950 kg/m3 and 1470 kg/m3. If each ofthe two materials occupies an equal volume, what is the mass of the cylinder?

(j) The density of water is 1000 kg/m3. A cube contains 500 kg of water. Determine thelength of each side of the cube.

(k) The density of iron is 7860 kg/m3. Determine the radius of an iron sphere of mass 100 kg.

3. (a) What is buoyant force?

(b) What is apparent weight and what effect does buoyant force have on the apparent weightof objects in a fluid?

(c) What is the condition for an object to sink in a liquid? What is the condition for an objectto float in a liquid?

(d) What is the statement of Archimedes’ Principle?

(e) A solid iron sphere of radius 25 cm is completely submered in water. The density of ironis 7860 kg/m3.

PhysicsFluids

Homework Ms. Heininger

i. Determine the weight of the sphere.

ii. Determine the buoyant force on the sphere.

iii. Determime the apparent weight of the sphere.

(f) Pg 279: Practice A: 1-4 ; Section Review: 1-5

(g) Pg 288-290: 1-9; 23-26

(h) A balloon inflated with helium gas (ρ = 0.2 kg/m3) has a volume of 6 × 10−3 m3. If thedensity of air is 1.3 kg/m3, what is the buoyant force exerted on the balloon?

(i) The density of ice is 0.92 g/cm3; and the density of seawater is 1.03 g/cm3. A large icebergfloats in Arctic waters. What fraction of the volume of the iceberg is exposed?

(j) An object weighs 15 N in air and 13 N when submerged in water. Determine the densityof the object.

(k) After a moving van drives onto a river ferry, the ferry sinks 0.0367 m. The length andwidth of the ferry are 15.24 m and 6.10 m, respectfully. Determine the weight of themoving van.

(l) A balloon is released from a tall building. The total mass of the balloon including theenclosed gas is 2.0 kg. Its volume is 5.0 m3. The density of air is 1.3 kg/m3.

i. What is the average density of the balloon?

ii. Will the balloon rise, fall, or remain stationary; and why?

iii. Determine the acceleration of the balloon.

4. (a) Define pressure. Write the formula relating pressure to force and area.

(b) Define Pascal’s Law.

(c) Pg 282: 1-4

(d) Define gauge pressure. Write the formula to determine gauge pressure.

(e) Define absolute pressure. Write the formula to determine the absolute pressure.

(f) Pg 283: 1-4

(g) Pg 288: 10, 12, 13, 14, 16, 21, 22, 27, 30

5. (a) What is laminar flow?

(b) What are the properties of an ideal fluid?

(c) Using the equation of continuity explain why the speed of a fluid depends on the cross-sectional area.

(d) Pg 286:1-4

(e) Pg 299: 18, 19, 28; Pg 300: 32