D. Acceleration describes how the velocity changes in time.
The correct answer of the given question above would be the first option. The statement that is true concerning atoms is that, atoms are made of even smaller substances called subatomic particles. Subatomic particles include neutrons, protons, electrons and atomic nuclei. Hope this answer helps.
The number of protons in an atom identifies the Atomic Number
Hope it helps!
Answer:(a)10 ft/s
(b)4 ft/s
Explanation:
Given
height of light 
height of man

From diagram



differentiate both sides

Tip of shadow is moving at the rate of

(b)rate at which length of his shadow is changing
Length of shadow is 
differentiating w.r.t time

