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:

Here we have to calculate the number of rotations made by earth around its own axis in the entire life time of a human being.
The average human life is 50 years .
Each year is 365.5 days
Hence 
=18,275 days
The earth rotates around its own axis in 23 hours 56 minutes and 4 second which is approximately equal to 24 hours or one days.
Hence one rotation takes one days.
⇒18,275 days =18,275 rotations
Hence the total number of rotations made by earth around its own axis in the life time of a average human life time will be 18,275 times
Answer:
the magnitude of the charge Q on each plate is 
Explanation:
Given that :
mass (m) = 
charge (q) = +0.155 µC = 
angle 
Area A on each plate = 0.0135 m²
From the diagram below;
----- equation (1)
Also by using Gauss Law ;

----- equation (2)
Combination equation 1 and 2 together ; we have



V = I · R
Voltage = (current) · (Resistance)
Voltage = (250 A) · (2.09 x 10⁴)
Voltage = 5,225,000 volts .
I may be out of line here, but I'm pretty sure
that the resistance is 2.09 x 10⁻⁴ .
Then
Voltage = 0.05225 volt (not 5 million and something)