102

N. Chari et al.

Example 2—Case of an Aluminium Foil

Aluminium foil thickness is 100 μ = 0.01 cm

Density ≈2.8 gm/cm³

Weight = 2.8 × 0.01 = 2.8 × 10⁻²gm

Weight = 28 mg

Wingbeat Frequency ϑ = 50 cps

a = r · θ

k = radius of gyration

I = ^Mb2

3

= Mk²

r =

b

√

3

If θ = 30⁰

∴a =

1

√

3

× ³⁰

180 ^{× π = 0.302 cm}

E = 2π²ma²ϑ² = 2 × π² × 0.028 ×

 1

√

3

2

× 50²

E = 460.15 ergs.

See Tables 7.1, 7.2, 7.3