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Essentially, a control variable is what is kept the same throughout the experiment, and it is not of primary concern in the experimental outcome. Any change in a control variable in an experiment would invalidate the correlation of dependent variables (DV) to the independent variable (IV), thus skewing the results.
Answer:

Explanation:
We need only to apply the definition of acceleration, which is:

In our case the final velocity is
, the initial velocity is
since it departs from rest, the final time is
and the initial time we are considering is 
So for our values we have:

Answer:
Approximately
(given that the magnitude of this charge is
.)
Explanation:
If a charge of magnitude
is placed in an electric field of magnitude
, the magnitude of the electrostatic force on that charge would be
.
The magnitude of this charge is
. Apply the unit conversion
:
.
An electric field of magnitude
would exert on this charge a force with a magnitude of:
.
Note that the electric charge in this question is negative. Hence, electrostatic force on this charge would be opposite in direction to the the electric field. Since the electric field points due south, the electrostatic force on this charge would point due north.
(a) The distance of the image formed by the concave mirror is 19.1 cm.
(b) The image formed is diminished and real.
<h3>
Image distance </h3>
The distance of the image formed by the concave mirror is calculated as follows;
1/f = 1/v + 1/u
1/v = 1/f - 1/u
1/v = 1/15 - 1/70
1/v = 0.05238
v = 1/0.05238
v = 19.1 cm
The image distance is smaller than object distance, thus the image formed is diminished and real.
Learn more about concave mirror here: brainly.com/question/13164847
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<span>First, she should put the sample in a test tube and place it in a centrifuge. This would cause the red blood cells to move to the bottom because of their higher density. Next, she would be able to decant the plasma and analyze it separately from the red blood cells.</span>