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.
Answer:
The Reynolds numbers for flow in the fire hose.
Explanation:
Given that,
Diameter = 6.40 cm
Rate of flow = 40.0 L/s
Pressure 
We need to calculate the Reynolds numbers for flow in the fire hose
Using formula of rate of flow


Where, Q = rate of flow
A = area of cross section
Put the value into the formula


We need to calculate the Reynolds number
Using formula of the Reynolds number

Where,
=viscosity of fluid
=density of fluid
Put the value into the formula


Hence, The Reynolds numbers for flow in the fire hose.
The answer is <span>higher than.
</span><span>A sound-producing object is moving toward an observer. The sound the observer hears will have a frequency higher than that actually being produced by the object.
Why?
</span>As the source of the waves is moving toward the observer, each of the successive wave crest<span> is emitted from a position closer to the observer than the previous wave.
Thus each wave takes slightly less time to reach the observer than the previous wave. So, the time between the arrival of successive wave crests at the observer is reduced, increasing the frequency. </span>
<span>The importance of discovering gravitational
waves are; one, we can measure the activity between two bodies in orbit in the
universe, two, scientist can estimate the merging of two bodies in the universe
every 15 minutes by using LIGO and three, we can know the behavior of other
bodies that we did not know exist.</span>