<h2>Right answer: a number and a unit</h2>
The measurement consists in <em>comparing a selected pattern with the object or phenomenon whose physical magnitude is going to be measured, to find out how many times the pattern is contained in that magnitude.</em> That is, it is about identifying or quantifying a particular characteristic or aspect of a particular object or construct.
Now, a well done measurement has two parts:
-The number gives us information about the quantity of the measurement, or in other words, the magnitude of the measurement and its precision.
-The units gives us information about the property that is being measured. This is quite important, because a measurement or result with no units is useless.
Note the units may be expressed with letter or symbols, depending on what we are measuring.
Answer:46.05 mm
Explanation:
Given

speed 
allowable shear stress 
Power is given by



From Torsion Formula

where J=Polar section modulus
T=Torque
=shear stress
For square cross section

where a=side of square

Substituting the values in equation 1



The total distance covered by the person is 12 times the height of each stair:

The work done by the person to climb the stairs is equal to the increase in his gravitational potential energy:

And therefore, the power generated by the person in 12 s is the work done divided by the time taken:

So, the correct answer is B.
The concept of work-energy theorem has become much of a fundamental principle in the field of physics, mechanics, and engineering. In addition, this theory primarily states that the change of kinetic energy of the system is equal to the sum of the work done that is acted by all forces on the object.