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Questions tagged [applied-mechanics]

Questions about using applied mechanics to model engineering problems.

419 questions
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Calculation of Clamping force from bolt torque

I'm trying to calculate the clamping force resulting from torquing a nut and bolt to a particular level. I have found this formula in various forms in a lot of places. $$T = KDP$$ $T$ = Torque (in-lb) $K$ = Constant to account for friction (0.15 -…
harry courtice
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What is the difference between the Polar Moment of Inertia, $ I_P $ and the torsional constant, $ J_T $ of a cross section?

This question is so fundamentally basic that I am almost embarrassed to ask but it came up at work the other day and and nearly no one in the office could give me a good answer. I was calculating the shear stress in a member using the equation,…
William S. Godfrey- S.E.
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From an engineering standpoint, what is the purpose of the indent in a coffee lid?

I've see the same lids every day but I never really thought about their construction. There is an indent in a "Solo Travel Lid" for coffee cups that is just above the hole that you drink the coffee from. You can see the crescent shaped indent in…
ruckus
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Easy nonlinear model for large deformation of a beam

I have a beam subject to twisting and/or bending forces as well as linear compression force along its main axis. It is modelled as an isotropic beam, but if anisotropic is not too far off then that's okay too. The beam is capable of large…
imacube
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Why are tremors of an earthquake felt more on upper floors?

Why are tremors of an earthquake felt most on the upper floors of a building in comparison to lower floors? Does this have something to do with a third class lever?
Debanshu Thakur
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Practical setup to measure angular velocity

I have got a spinning top from a Canadian manufacturer, and I am deeply amazed by how neatly it spins. My interest in physics has led me to try to find out at what top speed I can spin the top and how that compares to other tops made from other…
DK2AX
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Why do we neglect the radial stress in case of a thin pressure vessel?

A cylindrical or a spherical pressure vessel, having inner diameter $d$ & thickness of wall $t$, is called thin if $\large \frac{t}{d}<\frac{1}{20}$. $\bullet$ Thin cylindrical pressure vessel hoop or circumferential stress $…
Harish Chandra Rajpoot
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"u" vs "n" orientation of channel profiles: why difference in strength?

For example, metal tape measures can be extended and stay straight when in a "u" orientation, but collapse the other way round. I presume the same phenomenon is why metal shelving has sheet metal on top, and flanges on the bottom rather than the…
Jayy
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Writing a filtered derivative term of the PID controller into the C++ code

Everywhere I look, be it a PID, lead, lag control or anything else, there are Simulink schematics with transfer functions. This is all nice for system response simulation, however currently I have to implement a PID control with a filtered…
bluecore
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Why does "potential energy" have the word "potential" in it?

Imagine a block of mass $m$ placed on the ground. I slowly lift it up to height $h$. The work done by me on the block is $mgh$. This amount of energy is now stored in the block when it is at height $h$. This energy is called the potential energy of…
Harshit Rajput
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How do suction cups work?

These are suction-mounting hooks. I want to visualize and understand how do they stick on walls. After these hooks stick on wall. Like we compressed them. How? Since gases are compressible up to a good finite limit. What makes it difficult for them…
Rider
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Dynamics Simple Pulley System - Stuck on the Process

Have spent hours poring over this homework question but am having difficulty getting the right process going to solve the problem. I don't really know where to start, and I'd really be grateful if someone could show me the ropes (pun intended ^_^).…
Elisa Accordino
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Adding a lubricant to an already lubricious material, how is CoF affected?

I have a dry film moly-graphite lubricant (CoF=.075) and a lubricious CVD coating (CoF=.05). The CoF of each of these lubricious materials was determined using the same ASME standardized test. The standardized test consists of: a plain steel object…
CBRF23
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Calculating torque needed to climb a graded hill

I've been designing an electric skateboard which is driven by only one of the rear wheels (for the moment). As I was picking out motors for the board, I soon realized I would need to find a balance between torque needed to climb hills, and RPM to…
Satchel
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Compound gear system ratio

This might be a stupid question, but I'm new to mechanics, so please bear with me. Suppose I have a compound gearing system defined in the image below (not to scale). The green gear is the driving gear, and the blue gear is a compound gear.…
Tom
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