Answer:
C. Both technicians A and B
Explanation:
From the physical definition, power is defined as the rate of a body doing work. It is expressed as
P = w/t watts
Where
w - is the work done or the energy of the system in joules
t - time
The unit of power is represented in watts.
Whenever there is a rate of change of energy in the system, it accounts for the efficiency of the power of the system.
Hence, the statements of both technicians are correct.
Answer:
The constant torque required to stop the disk is 8.6 N-m in clockwise direction .
Explanation:
Let counterclockwise be positive direction and clockwise be negative direction .
Given
Radius of disk , r = 1.33 m
Mass of disc , m = 70.6 kg
Initial angular velocity , 
Final angular velocity , 
Time taken to stop , t = 2.75 min
Let
be the angular acceleration
We know

=>
=>
Torque required to stop is given by

where moment of inertia ,
=>
Thus the constant torque required to stop the disk is 8.6 N-m in clockwise direction .
Option C is the right answer
B. To have an earthquake there must be a fault line (where two or more tectonic plates meet) so if San Fran. has earthquakes they’re on a fault line.