Expert talks № 5. 🤓 Construction of the motorized test stand to reveal substandard rubbers.

[igorponger]

Let’s solve the problem step by step.

Given:

• rotational speed of the shaft n=15 revolutions per minute (rpm);
• shaft diameter d=5 mm.

Find: the linear speed of the free end of the thread V (mm/min).

Solution:

1. Use the formula for linear speed of a point on a circle:

V=π⋅d⋅n,

where:

• V — linear speed (mm/min),
• π≈3,1416,
• d — shaft diameter (mm),
• n — rotational speed (rpm).

1. Substitute the known values:

V=3,1416⋅5⋅15.

1. Perform the calculations:

• first, multiply 3,1416 by 5: 3,1416⋅5=15,708;
• then multiply the result by 15: 15,708⋅15=235,62.

1. Round the result to one decimal place: V≈235,6 mm/min.

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Answer: with a shaft diameter of 5 mm and a rotational speed of 15 rpm, the free end of the thread moves at a speed of 235.6 mm/min.

If you’d like, I can perform calculations for other parameters or explain any step in more detail

Hi, friends
Hereby we gonna to set up a regular audit for the rubbers being now sold on general market. Yes, there are many evidences the rubber manufacturers delivering substandard products on market, far different from those ITTF approved. Truth to say, ITTF does have no effective audit so far , we can see a lot of false products being now sold on general market. There are many factual evidences the rubber makers oftentimes delivering a substandard products on market, far different from those ITTF approved. ITTF does have no effective audit so far , we can see a lot of false products on market whose quality was found far different from original condition. Sorry.