Answer:
R = 5.73 m
Explanation:
For an angle of rotation through 21 degree we know that
arc length is given as

now we know that
Arc = 2.1 m
Angle = 21 degree

so now we have



The statement that best describes how the windmill technology benefits the environment is this: WINDMILLS DO NOT POLLUTE THE ENVIRONMENT.
Constructing a windmill involves harnessing the power of the wind to generate electricity. This type of electricity generation has no side effects whatsoever. It is environmental friendly and does not pollute the environment.
Answer: Only Tech B is correct.
Explanation:
First, tech A is wrong.
The circuits that can be compared with links in a chain are the series circuit, and it can be related to the links in a chain because if one of the elements breaks, the current can not flow furthermore (because the elements in the circuit are connected in series) while in a parallel circuit if one of the branches breaks, the current still can flow by other branches.
Also in a parallel circuit, the sum of the currents of each path is equal to the current that comes from the source, so Tech B is correct, the total current is equal to the sum of the currents flowing in each branch of the circuit.