Answer:
The appropriate solution is "61.37 s".
Explanation:
The given values are:
Boat moves,
= 10 m/s
Water flowing,
= 1.50 m/s
Displacement,
d = 300 m
Now,
The boat is travelling,
= 
= 
Travelling such distance for 300 m will be:
⇒ 

On putting the values, we get


Throughout the opposite direction, when the boat seems to be travelling then,
= 
= 
Travelling such distance for 300 m will be:
⇒ 

On putting the values, we get


hence,
The time taken by the boat will be:
= 
= 
From the given equation we can deduce what changes will occur if the frequency of the sound is doubled
V= f (λ)
Speed = frequency. Wavelength
When the frequency is doubled, speed will not change. Because speed depends on factors like temperature, air pressure, density of the gas. Since all these factors are unchanged thus speed will remain unchanged
Frequency is the number of waves produced per second. Frequency and wavelength are inversely proportional .Thus, if the frequency is doubled the wavelength would be halved.
The correct answer for #2 is C the magnetic force will be strongest on box #1.