Answer:
The value of new value of angular speed of merry go round.
= 0.96 
Explanation:
Given data
r = 1.4 m
Moment of inertia
= 265 kg - 
11 RPM


= 1.15 
From conservation of momentum principal
------- (1)



Put all the values in equation (1)
265 × 1.15 = 317.92 × 
= 0.96 
This is the value of new value of angular speed of merry go round.
I believe destructive interference
Let's use the mirror equation to solve the problem:

where f is the focal length of the mirror,

the distance of the object from the mirror, and

the distance of the image from the mirror.
For a concave mirror, for the sign convention f is considered to be positive. So we can solve the equation for

by using the numbers given in the text of the problem:



Where the negative sign means that the image is virtual, so it is located behind the mirror, at 8.6 cm from the center of the mirror.
Answer:
T = 60 s
Explanation:
There are 6 poles on the track which are equally spaced
so the angular separation between the poles is given as


so the angular speed of the train is given as


now we have time period of the train given as


