Questions tagged [applied-mechanics]

Questions about using applied mechanics to model engineering problems.

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how to fix an object at either 90degree or 0 degree

my problem is i donot know how to let the blue colored object be fixed at either 0 or 90 degree. i dnot want to be moveable at any degree like 30, 40 , or 50 degree either 0 or 90 degree. i have tried ...
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Lifting a thick rubber sheet - alternative to feedback actuators

Objective To create any shape via computer software communication to the top surface of a one inch thick rubber surface using a series of tools set underneath the same surface. Tools Presently working ...
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How to limit rpm to 100 on bi-directional input shaft no matter the torque up to 10hp. Right angel gear box. 1:6 increaser rpm output 600rpm

How to limit rpm to 100rpm on bi-directional input shaft no matter the torque, up to 10hp. Right angel gear box. 1:6 increaser rpm output 600rpm
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How to use low pass filter in lock-in amplifier?

I am doing the pump-probe experiment.After the reflection of probe beam from the sample it is passed through photodiode and then to lock-in amplifier. Now I need to extract unnecessary noise from ...
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How to find the displacement of an arbitrary point on a spring?

Consider a spring fixed from end A and pulled from the other end B. The displacement of the end B of the spring is $x$. If I take a point at a distance $l_1$ from end A, how can I determine the ...
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How to Calculate Damping Ratio and Natural Frequency of a Mass Spring Damper system, excluding air resistance?

In summary, I need the damping ratio and damped frequency of a system excluding air resistance, as the system will be operating in a vacuum. The system can be modeled as a mass-spring-damper, and the ...
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Could a downwind cart, or “push-me, pull-me” boat of a substantially heavier size be propelled with the use of a CVT, or continuous gear?

As broadly proven now before the academia, a vehicle including a boat or cart (probably a glider too) can move faster than the speed of wind up to about 2.5-2.8 times with a propeller generating lift ...
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Does the surface finish of the strings on a musical instrument impact the timbre?

Suppose we are testing out different unwound strings on a piano. Each of the tested strings is made of the same material, has the same length, same diameter, density, etc., the only difference being ...
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Problem of lifting of a body using 4 strings

I have a solid object that has been lifted to a hieght by 4 strings. I know the lifting point and the 4 corners of the object. Also the mass and the center of the gravity location of the object is ...
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Does the inertia of a beam section include the material density?

Sorry but I'm a little rusty. When solving a beam of any type of section, must the density be included in the moment of inertia of the section? For example, if I see Navier's formula, I would say ...
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how much pounds of pressure does a screw on perfume bottle cap vs a mechanically applied perfume bottle spray mechanism for a bottle exert?

What would be the difference in pressure between a screwed on bottle cap like the ones you see on a refillable perfume bottle screw on top such as this https://www.ebay.co.uk/itm/154178728592?hash=...
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Are there any advantages of using BEM for contact problem over FEM, apart from lesser computational cost?

FEM - Finite Element Method BEM - Boundary Element Method If we had access to "enough" computational resources (to discretize the entire volume domain in FEM to the same degree of fineness, ...
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How to calculate the degrees of freedom, constraints and the generalized coordinates in this dynamic system

The rope lengths are taken to be constant. Solution: $N$ particles with $k$ constraints. . Then the Degree of Freedom (DOF) is $3N-k$. In Figure 1, we have two particles $m_1$ and $m_2$, so $N=2$. But ...
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Incremental encoder with memory

I'm working on a robotics project. In this project we need to control the angle position of the wheels. We are going to use an incremental encoder (we didn't find an absolute encoder that was able to ...
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Calculation on gearbox design

I want to design a gearbox of 70hp input motor and speed of 1400rpm. The gearbox ratio is 1:10 of 2 stage parallel arrangements. How do I calculate for the teeth, modules and other requirements ...
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what is the minimum number of reinforcement bars in a circular tie rod?

I know that the minimum number of reinforcement bars in circular concrete section of columns are 6, is it the same for circular tie rod section?
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Velocity of blocks under different situations

Height of all blocks is 100m. CASE 1: Blocks are at a distance of 100m in height. When they reach the ground , velocity of 1st block must be higher than velocity of second block due to the extra ...
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Calculating torque in planetary gearbox

It's my understanding that in a planetary gearbox, force moves through the system via four mechanisms: the ring gear, the planet gears, the planetary carrier, and the sun gear. I'm trying to ...
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Work done by a force in a deformable body

Consider a deformable body that is acted upon by several forces at different points of application. Under these forces, the body remains at rest but deforms and the particles have some displacement. ...
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Is kinetic energy on a body in vacuum = 0?

We know kinetic energy =$\frac{1* mv^2}{2}$- $\frac{1* mu^2 }{2}. $. u=initial velocity & v=final velocity. So , for a body in uniform translational motion I.e acc=0 & velocity is constant. ...
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How to solve this complicated truss system?

Below is a truss I simulated in a truss calculator. I'm just wondering, how to solve for the compression and tension of each member and are there any method that can solve this? My solution is I ...
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Center of gravity

Say an aircraft without its engines has a mass of 118 tonnes and balances on its rear wheels only. This must mean the center of mass of the aircraft without its engines is directly above the rear ...
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What should be the mass of block A so that the system stays at rest?

Q: What should be the mass of block A so that the system stays at rest ? Conditions: i) No normal force is present at point of 2kg mass. It doesn’t mean N=0. ii) No friction , mass of string & ...
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How to Calculate Approximate Fuel Consumption from Engine Specs

I have a marine diesel engine, and I'd like to calculate the approximate fuel consumption based on the size of the engine, at a given number of RPM - specifically for the cruising recommended cruising ...
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How to replace these two forces with one force?

Here, $P>Q$. $O$ is the center of mass of the rigid and uniform bar/stick. As $P>Q$, the resultant is situated to the right of $\vec{P}$ and is parallel to $\vec{P}$. The magnitude of the ...
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I have a question regarding moments and centre of mass

Lets say a plane had 2 engines located 9m ahead of its rear wheels. Give each engine a mass of 7.5 tonnes. A force of 147150N will act 9m ahead of the rear wheels. lets say the aircraft was 133 tonnes ...
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Does the constraint equations written for pulley mass system can be any coordinate system other than rectangular

This is an example problem from the book vector mechanics for engineers. I had a doubt that how the position vectors for A and position vector B relative to A defined. That is the equation which is ...
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Is there a way to solve this complex statics problem algebraically?

This problem can be solve in 2 ways either I solve it with vectors which would be relatively painful and more time consuming and the other faster way is algebraically but I faced a problem when trying ...
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Modelling a Simple Translational System

I posted this on stack exchange physics, sadly no one has answered so I thought I'd try my luck here. I am trying to model the following translational mechanical system in I/O form, however I am ...
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Stress-strain Curve Interpretation

A significant barrier to my understanding of typical engineering stress vs. engineering strain curves is that for certain values of stress, there are multiple values of strain (i.e., the stress-strain ...
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Eight bar Linkage (Analytical solution)

Good morning, I'm trying to solve this problem of kinematics of an eight bar linkage through the analytical method. I don't want that you perform the calculation, only I would like to have a advice ...
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How to calculate the pressure applied in a compressible fluid?

If I am trying to figure the pressure needed contain a fluid like hydrogen in a cylindrical tank, how would calculating this go on? As Hydrogen is compressible to a differing amount than other ...
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Why does the string having length C not have an impact on the overall system?

The Q: Given: a1 and a2 are the accelerations of mass 8 kg , 2 kg respectively. i) Total Length of Sting $L=4 x_{1}+2 x_{2}+C$ ii) $\frac{d L}{d t}=\frac{4 d\left(x_{1}\right)}{d t}+\frac{2 d\left(x_{...
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Why is the direction of static friction towards centre in case of circular turning?

Here , a car turning on a circular track. I have marked all the kinds of friction , velocity happening in the diagram. For the front wheels , VT (Tangential velocity) ,Vr(Radial velocity) , VR(...
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Why is direction of velocity in front direction

These are how circular turning tracks look like. Now , according to my textbook: This is how it looks like. But I argue upon each & every point of it. Here , the car is turning but it’s ...
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Derivation of static & kinetic friction formula

We know formula of static friction & kinetic friction = μsN and μkN. I have searched online a lot about them. I do know what is the formula & how to use it but I couldn’t find any article ...
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For pure rolling , Proof for every point on wheel has velocity = vc + wr

There are 2 texts I have seen for every point on wheels finding out the exact velocity of certain points. The theory states for all is that : Every point on wheel has total v = rotational + ...
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Understanding velocity of points of wheel

I am very grateful to all for helping me out. Thank you. Also , It will be quicker for me to understand if you tell where at which point am I going wrong or right ? This way , I know exactly how much ...
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Energy consumed by a two-link planar manipulator with feedback control

I was carrying out a problem in which I have a fully actuated two link manipulator, so with an independent servo motor for each link that allows rotation in one direction and another (positive for ...
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Why is velocity of wheel = v0+wr?

The case we have is : A wheel is kept in a box. There are two images given. Given below are conditions of the first image: Velocity at which the wheel is turning. $\frac{d s}{d t}=\frac{d \vec{\...
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mechanism design for matrix of adjustable direction pointer

I need to construct a matrix of light pointers, each one aims in specific direction, and each pointer direction will be adjusted thousands times, size is flexible could be millimeters or centimeter ...
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Automatic Tissue Dispenser

My father is a software engineer and yesterday he asked me a question to test me, that I cannot, for the life of me, seem to figure out. He told me that I need to make a tissue paper dispenser that, ...
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Calculate effect of drag on ball in motion

So I’ve been trying to work out the range of a ball that has been projected by two spinning discs please when accounting for drag- This is what I got so far: $V=V\cos\theta$, $T=2V\sin\theta/g$ , and $...
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Root diameter and the base diameter of gear and pinion

In my design of a spurgear the root diameter in pinion is less than the base diameter but in the gear the base diameter is less than the root diameter. Why?
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Designing a grabber

I designed a grabber for grabbing strings and yarns. the movement that I need is straight up and down to grab a piece of yarn. I wanted to know if this model (in the video) works in real life or not. ...
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Question about theory of machines (kinematic diagrams)

Can I draw this part of kinematic diagram in this way, knowing that bolded W is a point of interest. so is my drawing true also? (my lines are in red and black(not bolded black))?
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where did the concrete splitting test calculated stress formulat come from?

In compression test of cylindrical concrete sample we get the normal stress easily by dividing failure force by sample cross section, but how we can explain the formulat used to determine tensile ...
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How to choose contravariant or covariant bases?

I completed an introductory course on continuum mechanics, but we did not delve into curvilinear coordinates with CM. However, when I read some publications I see the stress-strain relationship is ...
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mechanical counter using ratchet (for a pinball machine)

I have built purely mechanical pinball machines before which used score compartments the balls would fall into to keep track of points. I am now trying to find a way to count points without losing the ...
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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 $h$...

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