a. all systems work together to stabilize the body
Answer:
7.39 m or 3.61 m
Explanation:
= Wavelength
f = Frequency = 90 Hz
v = Speed of sound = 340 m/s
Path difference of the two waves is given by

Velocity of wave


So, the location from the worker is 7.39 m or 3.61 m
The work done by the battery is equal to the charge transferred during the process times the potential difference between the two terminals of the battery:

where q is the charge and

is the potential difference.
In our problem, the work done is W=39 J while the potential difference of the battery is

, so we can find the charge transferred by the battery:
The amount of heat needed to increase the temperature of a substance by

is given by

where m is the mass of the substance, Cs is its specific heat capacity and

is the increase of temperature.
If we re-arrange the formula, we get

And if we plug the data of the problem into the equation, we can find the specific heat capacity of the substance: