The answer is destructive interference. You have this for both C and D. I suspect one of C or D is supposed to be constructive interference... But destructive interference is the answer
Answer:
Time period for Simple pendulum, 
Explanation:
The Simple Pendulum
Consider a small bob of mass
is tied to extensible string of length
that is fixed to rigid support. The bob is oscillating in the plane about verticle.
Let
is the angle made by string with vertical during oscillation.
Vertical component of the force on bob,
Negative sign shows that its opposing the motion of bob.
Taking
as very small angle then, 
Let
is the displacement made by bob from its mean position ,
then, 
so,
........(1)
Since, pendulum is in hormonic motion,
as we know, 
where
is the constant and 
.........(2)
From equation (1) and (2)


Since, 


Answer:
b. 84 minutes
Explanation:
= Centripetal acceleration = 9.81 m/s²
r = Radius of Earth = 6378.1 km
v = Velocity
Centripetal acceleration is given by

Time period is given by

The time period of Earth’s rotation would be 84.43835 minutes
Answer: C) N: Electrical energy and M: Kinetic energy
Explanation:
I did it last year. I thinks its A