Answer:
It is C on edge.
Explanation:
Because I just figured it out and got it right and because it says so in the link provided from the question.
if rebecca stands in front of david at a distance of do and david perceives the position of rebecca at di, di will be +84 cm
<h3>What is focal length ?</h3>
How strongly light converges or diverges depends on an optical system's focal length, which is the inverse of optical power. A system with a positive focus length is said to converge light, whereas one with a negative focal length is said to diverge light.
focal length = +60 cm
magnification m = -0.40
focal length being positive an magnification negative.
given lens is a convex lens.
for a lens
m = di/do and 1/f = (1/di) - (1/do)di
= -0.4do1/f = (1/-0.4do) - 1/do do
= -210 cmdi = -0.4 * -210
di = +84 cm
To learn more about focal length go to - brainly.com/question/25779311
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Rocks and sediments I believe
Edwin Hubble calculated the expansion rate of the
universe. The evidence that he base his calculation is the differences in
redshift for galaxies. The answer is letter B. the red shift of galaxies was
directly proportional to the distance of the galaxy from earth. It means that bodies farther away from Earth
were moving away faster. The Hubble’s constant is the ratio of distance to
redshift equal to 170 kilometers per second per light year of distance.
Answer:
a)
, b)
, c) 
Explanation:
a) The system have a simple armonic motion, whose position function is:

The velocity function is determined by deriving the position function in terms of time:

The acceleration function is found by deriving again:

Let assume that
. The following nonlinear system is built:



System can be reduced by divinding the second and third expressions by the first expression:


Now, the last expression is divided by the first one:

b) The mass of the block is:



c) The phase angle is:


The amplitude is:

