Given:
initial angular speed,
= 21.5 rad/s
final angular speed,
= 28.0 rad/s
time, t = 3.50 s
Solution:
Angular acceleration can be defined as the time rate of change of angular velocity and is given by:

Now, putting the given values in the above formula:


Therefore, angular acceleration is:

Sound waves actually travel much faster in water than air, but words and the direction of the noise are distorted.
Odd though it seems at first, gravity is pulling the cat down while the floor is pushing the cat up - in equal amounts. Forces are absolutely acting on the cat but they balance - so there is no net force.
Answer:
a)θ=71.89°
b)NO
Explanation:
Given that
For glass n= 1.38
We know that for air n'=1
The angle for total internal reflection θc given as
sin θc=n'/n
By putting the values
sin θc=n'/n
sin θc=1/1.38
θc=46.43°
n'sinθ = n sinθref
sinθref = cosθc
n'sinθ = n cosθc
1 x sinθ =1.38 x cos 46.43°
θ=71.89°
b)
NO
<u>Answer:</u> Below 12m of depth, the submarine has to submerge so that it would not be swayed by surface waves
<u>Explanation:</u>
To avoid the surface waves, a submarine has to submerge below the wave base. It is the position below which the motion of the waves is negligible.
This wave base is equal to half of the wavelength. The equation becomes:
Wave base = 
We are given:
Wavelength = 24 m
Putting values in above equation, we get:
Wave base = 
Hence, below 12m of depth, the submarine has to submerge so that it would not be swayed by surface waves