An athlete is working out in the weight room. He steadily holds 50 kilograms above his head for 10 seconds. Which statement is t
2 answers:
Answer: The true statement form the given statements is "the athlete is not doing any work because he does not move the weight.".
Explanation:
The formula for work done is as follows,
Here, F is the force, s is the displacement and theta is the angle between force and displacement.
In the given problem, an athlete holds 50 kg on his head for 10 seconds. The angle between force and displacement is 90 degree.
In this case, the work done is zero.
Therefore, the athlete is not doing any work because he does not move the weight.
You might be interested in
Answer:
Using the new cylinder the heat rate between the reservoirs would be 50 W
Explanation:
- Conduction could be described by the Law of Fourierin the form:
where
is the rate of heat transferred by conduction,
is the thermal conductivity of the material,
and
are the temperatures of each heat deposit,
is the cross area to the flow of heat, and
is the distance that the flow of heat has to go.
- For the original cylinder the Fourier's law would be:
, and if
, then the expression would be:
where
is the diameter of the original cylinder, and
is the length of the original cylinder.
- For the new cylinder, in the same fashion that for the first, Fourier's Law would be:
,where
is the heat rate in the second case,
and
are the new diameter and length.
- But,
and
, substituting in the expression for
.
- Rearranging:
.
- In the last declaration of
, then:
.
- <u>It should be noted, that the temperatures in the hot and cold reservoirs never change.</u>