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


Answer:
42.0×10² second²
Explanation:
Here, time is given in milisecond
(64800 ms)²
= 4199040000 ms²
The SI unit is seconds
1 second = 1000 milisecond



42.0×10² second²
Answer: Scattering reflection
Sunlight reaches earth's atmosphere and is scattered in all directions by all the gasses and particles in the air. Blue light is seen more than others because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
Explanation:
The line is called equator.
Answer:
Explanation:
All matter is made up of atoms, which are turned up of protons, neutrons and electrons.
They bond together to make up matter