Answer:
According to the travellers, Alpha Centauri is <em>c) very slightly less than 4 light-years</em>
<em></em>
Explanation:
For a stationary observer, Alpha Centauri is 4 light-years away but for an observer who is travelling close to the speed of light, Alpha Centauri is <em>very slightly less than 4 light-years. </em>The following expression explains why:
v = d / t
where
- v is the speed of the spaceship
- d is the distance
- t is the time
Therefore,
d = v × t
d = (0.999 c)(4 light-years)
d = 3.996 light-years
This distance is<em> very slightly less than 4 light-years. </em>
The acceleration of the body is 2 m/s^2 while the deceleration is - 1.2 m/s^2.
<h3>
What is the acceleration?</h3>
Let us recall that the acceleration is the change in the speed of a body with time. We have been told that the body accelerates for 3s and then decelerates to 2s. This implies that the total time that the object spent in motion is 5 s.
Thus;
v = u + at
v = final velocity
u = initial velocity
a = acceleration
t = time taken
v - u/t = a
a = 6 - 0/3
= 2 m/s^2
Again;
v - u/t = a
a = 0 - 6/5
a = - 1.2m/s^2
Learn more about acceleration:brainly.com/question/12550364
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<h3 />
A type of material that tries to prevent the flow of thermal energy is called an insulator.
To solve this problem we will use the concepts related to Magnification. Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a calculated number also called "magnification".
The overall magnification of microscope is

Where
N = Near point
l = distance between the object lens and eye lens
= Focal length
= Focal of eyepiece
Given that the minimum distance at which the eye is able to focus is about 25cm we have that N = 25cm
Replacing,


Therefore the correct answer is C.
It probably is the actual answer.