Resistance in wires causes thermal energy. The correct
answer between all the choices given is the third choice or letter C. I am
hoping that this answer has satisfied your query and it will be able to help
you in your endeavor, and if you would like, feel free to ask another question.
I believe the answer is a
Answer:
The function has a maximum in 
The maximum is:

Explanation:
Find the first derivative of the function for the inflection point, then equal to zero and solve for x




Now find the second derivative of the function and evaluate at x = 3.
If
the function has a maximum
If
the function has a minimum

Note that:

the function has a maximum in 
The maximum is:

Answer: 6.36
Explanation:
Given
Radius of grindstone, r = 4 m
Initial angular speed of grindstone, w(i) = 8 rad/s
Final angular speed of the grindstone, w(f) = 12 rad/s
Time used, t = 4 s
Angular acceleration of the grinder,
α = Δw / t
α = w(f) - w(i) / t
α = (12 - 8) / 4
α = 4/4 = 1 rad/s²
Number of complete revolution in 4s =
Δθ = w(i).t + 1/2.α.t²
Δθ = 8 * 4 + 1/2 * 1 * 4²
Δθ = 32 + 1/2 * 16
Δθ = 32 + 8
Δθ = 40 rad/s
40 rad/s = 40/2π rpm = 6.36 rpm
Therefore, the grindstone does 6.36 revolutions during the 4 s interval