It is gravity¿ what is the question?
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
I think it's a) 1st Newton's law... so sorry if it's wrong...
On an electromagnetic spectrum, one of its noticeable trends is that the wavelength increases with decreasing energy and the wavelength decrease with increasing energy. Furthermore, gamma rays have high energy and short wavelengths while microwaves have low energy and long wavelengths.
False, there are always pros and cons to research