Answer:
The beam of light is moving at the peed of:
km/min
Given:
Distance from the isalnd, d = 3 km
No. of revolutions per minute, n = 4
Solution:
Angular velocity, 
(1)
Now, in the right angle in the given fig.:
Now, differentiating both the sides w.r.t t:
Applying chain rule:
Now, using 
and y = 1 in the above eqn, we get:
Also, using eqn (1),
Answer:
15 N
Explanation:
According to Newton's third law of motion, to every action, there is an equal and opposite reaction. This reaction is equal in magnitude to the force acting but in an opposite direction.
Now, if the book weighs 15 N, an opposite equal force will be: N = -15 N
But the magnitude of this will be the absolute value which is 15N.
#1. A. Waxing crescent.
#2. 1.
#3. C.
#4. C.
