Measurement of physical quantity With a steel tape measure and a piece of chalk, you are not allowed to go through any mathematical calculation, and you are not allowed to open the oil barrel. How can you directly measure the longest straight line distance in the cylindrical closed thin oil barrel?

Measurement of physical quantity With a steel tape measure and a piece of chalk, you are not allowed to go through any mathematical calculation, and you are not allowed to open the oil barrel. How can you directly measure the longest straight line distance in the cylindrical closed thin oil barrel?

First measure the circumference to get the diameter D of the bottom surface, and then measure the height H. then the longest straight line distance is the length of the hypotenuse of the Pythagorean theorem of height and diameter. S ^ 2 = D ^ 2 + H ^ 2. What's the use of chalk? Do you calculate the diameter and height on the ground? -. Oh, without mathematical calculation, I'm wrong

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If Xiaohua wants to compete with each other in the rope skipping competition, the physical quantities that must be measured in the activity are: quality, strength, strength, etc______ 、______ ; required measuring tools: scale______ 、______ The expression of measured power is as follows:______ ．

Class rope skipping competition, to compare who the power of rope skipping is the largest, the application of scale to measure the quality of students m, scale to measure the height of jump h, with a stopwatch to measure the number of times of rope skipping in t time n, then the power expression P = wt = nght = nmght. So the answer is: the height of jump; the number of rope skipping in t time; scale; stopwatch; P = nmght

If you want to move the box from the first floor to the third floor, you need to measure the power of the work done on the box. What is redundant in the following physical quantities
A. Measure the mass of the box m B. measure the total length of the stairs L
C. Measure the vertical height from the first floor to the third floor, H D. measure the time taken by Xiaoyun to go upstairs, T. what I want to know is why B is wrong, calculating the distance traveled, s should be right. He doesn't mean calculating power, P = w / T = f * s / T
And S (distance) I think it should be the length of the stairs for people to carry boxes
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People are forced upward, so consider the height of the box rising in the vertical direction
P = GH / T, no work in horizontal direction
By the way, similar to the example of crane, the work done in oblique motion is GH