True or false The forehand and backhand strokes are commonly used for serving in Table Tennis.
1 answer:
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Answer:
speed of star is 1.37 × m/s
it is approaching to earth because wavelength of star is decreasing than rest
if emit same wavelength it does not move anywhere
it will remain steady condition with respect earth
Explanation:
given data
wavelength = 656.5 nm
rest wavelength = 656.8 nm
to find out
the speed of the star , is it approaching
solution
we know here equation that is
wavelength shift / wavelength at rest = velocity of source / speed of light
so put all value and find
velocity of source = 3 × × 3 ×
/ 656.8 ×
velocity of source star = 1.37 × m/s
and
it is approaching to earth because wavelength of star is decreasing than rest
and
if emit same wavelength it does not move anywhere
it will remain steady condition with respect earth
Answer:
The rate of change of the shadow length of a person is 2.692 ft/s
Solution:
As per the question:
Height of a person, H = 20 ft
Height of a person, h = 7 ft
Rate = 5 ft/s
Now,
From Fig.1:
b = person's distance from the lamp post
a = shadow length
Also, from the similarity of the triangles, we can write:
Differentiating the above eqn w.r.t t:
Now, we know that:
Rate =
Thus