I believe it is A :) hope this helped
Answer:
The acceleration is 11.25 km/hr
Explanation:
Divide the velocity over time to find the acceleration. The bus is accelerating 11.25 km/hr per second in the range of 8 seconds
To solve this problem we will apply the concepts of linear mass density, and the expression of the wavelength with which we can find the frequency of the string. With these values it will be possible to find the voltage value. Later we will apply concepts related to harmonic waves in order to find the fundamental frequency.
The linear mass density is given as,



The expression for the wavelength of the standing wave for the second overtone is

Replacing we have


The frequency of the sound wave is



Now the velocity of the wave would be



The expression that relates the velocity of the wave, tension on the string and linear mass density is





The tension in the string is 547N
PART B) The relation between the fundamental frequency and the
harmonic frequency is

Overtone is the resonant frequency above the fundamental frequency. The second overtone is the second resonant frequency after the fundamental frequency. Therefore

Then,

Rearranging to find the fundamental frequency



Thinking the small glass bead as a single point charge, the electric field generated by it is given by

where

is the Coulomb's constant

is the charge of the bead

is the distance at which we calculate the field.
Using these data, we find:
Answer:
7) λ = 0.5 m, 8) f = 4.8 10¹⁴ Hz
Explanation:
The speed of an electromagnetic wave is
c = λ f
where c is the speed of light in vacuum c = 3 10⁸ m / s
7) indicate the frequency f = 6.0 10⁸ Hz
we do not know the wavelength
λ = c / f
we calculate
λ = 3 10⁸ / 6.0 10⁸
λ = 0.5 m
8) indicate the wavelength λ = 6.25 10-7 m
we do not know the frequency
f = c / λ
we calculate
f = 3 10⁸ / 6.25 10⁻⁷
f = 0.48 10¹⁵ Hz
f = 4.8 10¹⁴ Hz