The work done by a rotating object can be calculated by the formula Work = Torque * angle.
This is analog to the work done by the linear motion where torque is analog to force and angle is analog to distance. This is Work = Force * distance.
An example will help you. Say that you want to calculate the work made by an engine that rotates a propeller with a torque of 1000 Newton*meter over 50 revolution.
The formula is Work = torque * angle.
Torque = 1000 N*m
Angle = [50 revolutions] * [2π radians/revolution] = 100π radians
=> Work = [1000 N*m] * [100π radians] = 100000π Joules ≈ 314159 Joules of work.
Answer:
Current, I = 0.0011 A
Explanation:
It is given that,
Diameter of rod, d = 2.56 cm
Radius of rod, r = 1.28 cm = 0.0128 m
The resistivity of the pure silicon, 
Length of rod, l = 20 cm = 0.2 m
Voltage, 
The resistivity of the rod is given by :


R = 893692.30 ohms
Current flowing in the rod is calculated using Ohm's law as :
V = I R


I = 0.0011 A
So, the current flowing in the rod is 0.0011 A. Hence, this is the required solution.
Answer:
2.2 meters
Explanation:
Potential energy, PE created by a charge, q at a radius r from the charge source, Q, is expressed as:

is Coulomb's constant.
#The electric field,
at radius r is expressed as:

From i and ii, we have:


#Substitute actual values in our equation:

Hence, the distance between the charge and the source of the electric field is 2.2 meters
Use Factor-Label Method:
8miles 63360 inches
---------- X --------------------- X
1 1 mile
2.54cm 1 meter
X ------------ X ---------------- X
1 inch 100 cm
1 km
----------------- = 12.87 km
1000meters
8 miles = 12.87 km