Answer:
The length of the bridge during the hottest part of summer is 
Explanation:
From the question we are told that
The length of the steel bridge is 
The temperature for this length is 
The temperature at summer 
The coefficient of linear expansion is 
Generally the change in length of the steel bridge is mathematically represented as

Substituting value


The length of the bridge in summer is mathematically evaluated as

Substituting values


The experiment was well designed.
<h3>What is an experiment?</h3>
An experiment is used to determine cause and effect relationships. We know that in this case, the research is aimed at being able to obtain the relationship that exists between the amount of nitrogen in the soil and the production of tomatoes per plant.
As we could see, the experiment includes a control that serves as a baseline for determining the validity of the results. Further more, the sunlight, water and soil were held constant. The experiment was even repeated further south to verify the results.
Based on a careful review of the experiment, the experiment was well designed.
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Answer:
it does happen, search in Google
Since the Units presented are not in the International System we will proceed to convert them. We know that,

So the speed in SI would be


The change in frequency when the wave is reflected is

Or we can rearrange the equation as

f' = Apparent frequency
f = Original Frequency
c = Speed of light


Replacing,


Since the waves are reflected, hence the change in frequency at the gun is equal to twice the change in frequency



Therefore the increase in frequency is 2979.63Hz
Answer:

Explanation:
According to Coulomb's law, the force of attraction between two point charges,
and
, separated by a distance
is given by

is a constant with a value of
.
When we substitute the values from the question,

This value is negative because it is in a direction towards the positive charge.
The work done in moving the electron from the nucleus is


This is negative because work is done on the electron, not by it.