Answer:
25.3 ft
Explanation:
The illustration of the problem is shown the attached image.
The length of the ladder can be calculated using the Pythagoras theorem:
The hypotenuse is the length of the ladder.
........1
Triangle ABC is similar to triangle AEF, hence:
BC = 
.................2
Substitute 2 into 1
= 
+ 
Let AE = x
= 
= 
Minimize L with respect to x.
2
= 
=
Answer:
76.74 Hz
Explanation:
Given:
Wave velocity ( v ) = 330 m / sec
wavelength ( λ ) = 4.3 m
We have to calculate Frequency ( f ):
We know:
v = λ / t [ f = 1 / t ]
v = λ f
= > f = v / λ
Putting values here we get:
= > f = 330 / 4.3 Hz
= > f = 3300 / 43 Hz
= > f = 76.74 Hz
Hence, frequency of sound is 76.74 Hz.
| Impedance | = √ [R² +(ωL)²]
R² = 6800² = 4.624 x 10⁷
(ωL)² = (2 · π · f · 2.3 · 10⁻³)²
= 2.0884 x 10⁻⁴ f²
| Z | = √[ (4.624 x 10⁷) + (2.0884 x 10⁻⁴ f²) ] = 1.6 x 10⁵
(1.6 x 10⁵)² = (4.624 x 10⁷) + (2.0884 x 10⁻⁴ f²)
(2.56 x 10¹⁰) - (4.624 x 10⁷) = 2.0884 x 10⁻⁴ f²
Frequency² = (2.56 x 10¹⁰ - 4.624 x 10⁷) / 2.0884 x 10⁻⁴
= 2.555 x 10¹⁰ / 2.0884 x 10⁻⁴
= 1.224 x 10¹⁴
= 122,400 GHz <== my calculation
11.1 MHz <== online impedance calculator
Obviously, I must have picked up some rounding errors
in the course of my calculation.
