1) In the reference frame of one electron: 0.38c
To find the relative velocity of one electron with respect to the other, we must use the following formula:

where
u is the velocity of one electron
v is the velocity of the second electron
c is the speed of light
In this problem:
u = 0.2c
v = -0.2c (since the second electron is moving towards the first one, so in the opposite direction)
Substituting, we find:

2) In the reference frame of the laboratory: -0.2c and +0.2c
In this case, there is no calculation to be done. In fact, we are already given the speed of the two electrons; we are also told that they travel in opposite direction, so their velocities are
+0.2c
-0.2c
Limestone and dolomite are the rocks present in the locations which leads to the formation of caves.
<h2>Formation of caves</h2>
The type of rocks that once existed in these locations are limestone and dolomite whereas the pH of the nearby groundwater is slightly acidic which is responsible for the formation of caves. Caves are formed by the dissolution of limestone due to acid rain.
<h3>Acid rain</h3>
Rainwater reacts with carbon dioxide from the air and percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone which become turn to form caves so we can conclude that Limestone and dolomite are the rocks present in the locations which leads to the formation of caves.
Learn more about caves here: brainly.com/question/7965722
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Incomplete question as the angle between the force is not given I assumed angle of 55°.The complete question is here
Two forces, a vertical force of 22 lb and another of 16 lb, act on the same object. The angle between these forces is 55°. Find the magnitude and direction angle from the positive x-axis of the resultant force that acts on the object. (Round to one decimal places.)
Answer:
Resultant Force=33.8 lb
Angle=67.2°
Explanation:
Given data
Fa=22 lb
Fb=16 lb
Θ=55⁰
To find
(i) Resultant Force F
(ii)Angle α
Solution
First we need to represent the forces in vector form

Total Force

The Resultant Force is given as

For(ii) angle
We can find the angle bu using tanα=y/x
So

Answer:
(a) Time t = 16.46 sec
(b) Time t =13.466 sec
(c) Deceleration = 
Explanation:
(a) As the train starts from rest its initial velocity u = 0 m/sec
Acceleration 
Final speed v = 80 km/hr

From first equation of motion v =u+at
So 
(b) Now initial speed u = 22.22 m/sec
As finally train comes to rest so final speed v=0 m/sec
Deceleration 
So 
(c) We have given that initial velocity = 80 km/hr = 22.22 m/sec
Final velocity v = 0 m/sec
Time t = 8.30 sec
So acceleration is given by

As acceleration is negative so it is a deceleration
Electrons are important to the electric current because they are able to move from one atom to another. When an atom loses an electron, it becomes positively charged and when an atom gains an electron, it becomes negatively charged.