20. To organize the calculation, we introduce the notion of density (which the students have probably seen

in other courses):

ρ =

m

V

.

(a) We tak e the volume of the leaf to be its area A multiplied by its thickness z.

With density

ρ = 19.32 g/cm

3

and mass m = 27.63 g, the volume of the leaf is found to be

V =

m

ρ

= 1.430 cm

3

.

We convert the volume to SI units:

1.430 cm

3

  1 m

100 cm



3

= 1.430

× 10

−6

m

3

.

And since V = A z where z = 1

× 10

−6

m (metric prefixes can be found in Table 1-2), we obtain

A =

1.430

× 10

−6

m

3

1

× 10

−6

m

= 1.430 m

2

.

(b) The volume of a cylinder of length  is V = A where the cross-section area is that of a circle:

A = πr

2

. Therefore, with r = 2.500

× 10

−6

m and V = 1.430

× 10

−6

m

3

, we obtain

 =

V

πr

2

= 7.284

× 10

4

m .

Document Outline

• Main Menu
• Chapter 1 Measurement
  • 1.1 - 1.10
    • 1.1
    • 1.2
    • 1.3
    • 1.4
    • 1.5
    • 1.6
    • 1.7
    • 1.8
    • 1.9
    • 1.10
  • 1.11 - 1.20
    • 1.11
    • 1.12
    • 1.13
    • 1.14
    • 1.15
    • 1.16
    • 1.17
    • 1.18
    • 1.19
    • 1.20
  • 1.21 - 1.30
    • 1.21
    • 1.22
    • 1.23
    • 1.24
    • 1.25
    • 1.26
    • 1.27
    • 1.28
    • 1.29
    • 1.30
  • 1.31 - 1.40
    • 1.31
    • 1.32
    • 1.33
    • 1.34
    • 1.35
    • 1.36
    • 1.37
    • 1.38
    • 1.39
    • 1.40
  • 1.41 - 1.44
    • 1.41
    • 1.42
    • 1.43
    • 1.44
• Chapter 2 Motion Along a Straight Line
• Chapter 3 Vectors
• Chapter 4 Motion in Two and Three Dimensions
• Chapter 5 Force and Motion I
• Chapter 6 Force and Motion II
• Chapter 7 Kinetic Energy and Work
• Chapter 8 Potential Energy and Conservation of Energy
• Chapter 9 Systems of Particles
• Chapter 10 Collisions
• Chapter 11 Rotation
• Chapter 12 Rolling, Torque, and Angular Momentum
• Chapter 13 Equilibrium and Elasticity
• Chapter 14 Gravitation
• Chapter 15 Fluids
• Chapter 16 Oscillations
• Chapter 17 Waves—I
• Chapter 18 Waves—II
• Chapter 19 Temperature, Heat, and the First Law of Thermodynamics
• Chapter 20 The Kinetic Theory of Gases
• Chapter 21 Entropy and the Second Law of Thermodynamics
• Chapter 22 Electric Charge
• Chapter 23 Electric Fields
• Chapter 24 Gauss’ Law
• Chapter 25 Electric Potential
• Chapter 26 Capacitance
• Chapter 27 Current and Resistance
• Chapter 28 Circuits
• Chapter 29 Magnetic Fields
• Chapter 30 Magnetic Fields Due to Currents
• Chapter 31 Induction and Inductance
• Chapter 32 Magnetism of Matter: Maxwell’s Equation
• Chapter 33 Electromagnetic Oscillations and Alternating Current
• Chapter 34 Electromagnetic Waves
• Chapter 35 Images
• Chapter 36 Interference
• Chapter 37 Diffraction
• Chapter 38 Special Theory of Relativity
• Chapter 39 Photons and Matter Waves
• Chapter 40 More About Matter Waves
• Chapter 41 All About Atoms
• Chapter 42 Conduction of Electricity in Solids
• Chapter 43 Nuclear Physics
• Chapter 44 Energy from the Nucleus
• Chapter 45 Quarks, Leptons, and the Big Bang