Questions tagged [statics]

Statics is branch of engineering concerned with the analysis of forces and moments on physical systems in static equilibrium.

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1answer
477 views

Normal force between two boards

This is a problem from the book Engineering Mechanics Statics vol-1 by Meriam Kraige The rectangular steel yoke is used to prevent slippage between the two boards under tensile loads $P$ .If the ...
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1answer
696 views

Car which can climb the ramp of higher inclination

Two automobiles both of which have the mass center located midway between the front and rear axles,are identical except that one is front-wheel-drive and the other is rear-wheel-drive.The cars are ...
3
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1answer
112 views

Force P required to slide the door if one of the wheel becomes frozen

I am solving problems from the book: Meriam Kraige Engineering Mechanics statics vol 1. The problem is as follows: The sliding door rolls on the two small lower wheels $A$ and $B$. Under normal ...
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1answer
122 views

Isn't a pin support supposed to prevent translation both horizontally and vertically?

I know that pins prevent horizontal and vertical translation and that rollers prevent only the vertical one. Therefore, what I do not understand here is that while the support at B reacts with two ...
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1answer
114 views

Suspended Shelf Problem

I'm attempting to create a suspended shelf. I need to determine the horizontal force at point A to determine whether or not the fasteners will fail. All members are rigid and the supports at A and B ...
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218 views

Finding the force in a cable of a rigid system

QUESTION (see attached image file): I got stuck when trying to find tension for part A; see my working below. and help me solve.
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1answer
2k views

Determine the reactions at A and C, knowing that α = 30º [closed]

QUESTION(see image attached): Really need help here can someone help me show how we get the solution as shown in the image file attached above. okay since I was asked by one of the users ...
2
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1answer
609 views

Solving truss using method of joints

So, this is the truss I have to solve, more precisely I have to find forces in all of the members of the truss. That is why I used method of joints. I started from the joint A and realised without ...
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1answer
111 views

Structural Analysis Conundrum

I am analysing the forces within a certain frame, and for some reason there do not seem to be sufficient equations of equilibrium to solve for all the internal forces. Is there something about this ...
2
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1answer
133 views

Equivalent Force: Hydraulic rams in H frame machine press

A 100ton H frame machine press can use 1x100 ton ram to exert this amount of force. Can 3x33 ton rams do the same job if they are applied to same area as the 100ton ram? Also in relation to a H ...
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2answers
825 views

How can we derive the formula of the centroid?

In order to find the coordinates of the center of an area, we can use this formula: $$\begin{align} \overline{x} &= \frac{\int x\text{d}A}{A} \\ \overline{y} &= \frac{\int y\text{d}A}{A} \...
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1answer
55 views

why does the body have an no angular acceleration if the applied force passes the center of mass?

While I was looking for the definition of the center of mass , I found this text : "If a single force acts on a    body and the line of action of the force passes through the centre of mass, the body ...
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2answers
41 views

Would friction forces impact a torque measurement transmitted through a gear box

I want to be able to detect very small torques placed on the end of a cantilever beam. These torques are very small - 1mg by 10cm. I am trying to make this on the cheap and use a load cell. I plan ...
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1answer
255 views

Burst pressure of a sphere

Is there a formula for the burst working pressure of a spherical pressure vessel that takes into account its material peoperties? It should be noted that this is not a concentric sphere design (it has ...
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1answer
5k views

How to find the reaction forces, moments and the displacement of the fixed beam with a link?

The beam is fixed on both ends and there is a link in the middle. There is a force F on the link. My approach to solve this problem: A free body diagram is cut at the link and made into 2 systems. ...
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0answers
190 views

Fluid Statics Problem

I have been attempting this question for a while now. Could anyone give me a hand? The question and the work I have done so far is below. My final "answer" is P (force required to keep the gate ...
2
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1answer
449 views

Reaction force on a beam

I have the following problem most of which I have calculated but have a difficulty with the beam under angle. The angle is 56,30 degress. I just cannot figure out how the forces there are acting - the ...
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2answers
859 views

Why is the truss member between two fixed supports zero?

If i first assume the member(far left) to not be zero and use method of joint at both points of constraint, with both constraints having unknown vertical reaction, it cannot be solved. Load and ...
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2answers
7k views

How to find reaction forces in trusses?

I'm stucked at trying to find the vertical reaction at top and bottom constraint, i know how to do the rest. Can you show me how?
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1answer
84 views

cut section method in truss

For moment about D , how could the FGF sin26.6 generate moment about D ? FGF sin26.6 is located above point D , right ? How could FGF sin26.6 generate moment about D ?
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3answers
1k views

Draw the FBD of the entire frame, assuming that friction and the weights of the members are negligible. How many unknowns appear on this FBD?

Draw the FBD of the entire frame, assuming that friction and the weights of the members are negligible. How many unknowns appear on this FBD? This is what I've tried so far. I have four unknowns. ...
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2answers
672 views

Drawing conclusions about 3d truss from 2d model

I am on the task of analysing the load capacity of a warren-ish truss bridge similar to this one. I do not, however, have the software or skill to model and analyse a 3D structure. I was wondering ...
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3answers
126 views

Finding downward force of lever bar

I am working on a DIY project, I am trying to replicate a bar compressor which for some reason is only sold in Europe so I thought it would be fun to make my own without having to waste so much ...
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1answer
60 views

Deformation of a fixed-fixed beam with perfectly plastic yield stresses

Here's the setup: The problem asks to find the relationship between the force $P$ and the displacement of B ($u_B$). I have done this correctly: $$P = \left(\dfrac{E_1A_1}{L_1}+\dfrac{E_2A_2}{L_2}\...
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2answers
5k views

How does a pulley (with friction) satisfy equilibrium?

In the picture shown : Suppose that there is a man applying a force $F$ in order to support the box using a cord that wraps over a frictionless pulley (the system is in equilibrium and nothing is ...
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Why do we ignore horizontal reactions at roller supports?

When talking about roller supports in a statics problem, we say that the roller prevents only the vertical translation of the beam, but not the rotation or the horizontal translation of it. So there ...
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1answer
159 views

Equilibrium of a Rod with an Actuator

I'm an EE student by trade, but I've started a project that requires some mechanical analysis, and I've run up against a bit of a wall in my calculations. The system in question that I'm looking at ...
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2answers
206 views

Why does a simple pin-ended triangular (arched/curved) beam deflect more due to secondary effects (non-linear analysis)?

I cannot wrap my head around this. I have made two simple models, a triangular (or curved or arched) beam that is pin ended and has a single point load of 1N downwards at it's center, and a flat beam ...
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1answer
2k views

Calculating the moments due to reaction forces on a bent beam

I am trying to solve the following problem: EXAMPLE 2.10 Determine the reactions on the beam in Fig. 2–30a. Assume $B$ is a pin and the support at $B$ is a roller (smooth surface). ...
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3answers
4k views

How should I position two shelf supports for the best distribution of load?

I'd like to mount a shelf on the wall. I have two shelf supports to do so, like this: Relative to the shelf, where do I place the (blue) supports to achieve the best distribution of load?
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1answer
217 views

Why is the moment of forces on a rigid body in static equilibrium must be zero about any point, even if the position of that point is not on the body

Why is it necessary for the moment of the forces on a rigid body in static equilibrium to be zero about any point, even if the position of that point is not on the body itself.
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2answers
527 views

Truss problem with multiple unknowns

So ive got the moments of : B: Vertical : $\sin(75)AB + \sin(45)BC = 33\text{ lbs}$ Horizontal : $\cos(75)AB = DB + \cos(45)BC$ D: Vertical: $\sin(60)DC + \sin(65)DE = 100\text{ lbs}$ Horizontal: $...
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2answers
311 views

Free Body Diagram Problem

I'm having trouble with this problem: G and a are given, and we are asked to calculate A, B and C. What I've Done: The first thing I tried was a free body diagram cutting through A and C to create ...
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3answers
116 views

How can the linear relationship between curvature and bending moments be verified?

As part of an experiment, I'm verifying the existence of a linear relationship between curvature and bending moments for three beams using different materials. The plotted data can be seen below. ...
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1answer
449 views

Static equilibrium and moment

I hope I'm asking this in the right place. I have the following problem: and am to calculate A,B & C so that the system is in static equilibrium. I calculated A without too many problems. My ...
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1answer
410 views

How do we solve a rigid body indeterminate structure?

In statics we consider the force deflection constraints (i.e. assuming the structure to be flexible) to generate equations in order to solve the extra degrees of indeterminacy. So, basically if we ...
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1answer
2k views

How to calculate area of cross section needed to sustain a point load on a beam?

Consider a beam that is simply supported at both ends by fixed supports and a point load is applied directly in the middle. The force (F), length of beam (L), Young's Modulus (E) and tensile and ...
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1answer
6k views

Derivation if the formula for the surface moment of inertia of an isosceles triangle

For a isosceles triangle with base b and height h the surface moment of inertia around tbe z axis is $\frac{bh^3}{36}$ (considering that our coordinate system has z in the horizontal and y in the ...
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2answers
2k views

Given the tensile strength of a rod, how do you calculate the max weight that can be hung from it?

Given a 3.25" long, 0.125" diameter rubber rod with tensile strength 1200 psi supported on both ends, how much weight can you hung from the middle of it without breaking it? (This is not homework I am ...
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1answer
86 views

What kind of connection allows rotation at only one end?

We are looking to connect a non spinning coolant pipe to a spinning drill pipe. The connector needs to spin on the end with the drill pipe but be stationary on the end with the coolant pipe. Is there ...
0
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1answer
130 views

Statics - Volume of a Revolution [closed]

The given problem asks for the Volume of the given figure below You have a plane figure that somewhat forms a Two-circular base Paraboloid with radii 20 and 12 cms respectively, and an altitude of 16 ...
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1answer
331 views

What does the accuracy and precision values for a pipette mean?

Is the accuracy interval the tolerance for the instrument? Does the precision interval indicate a single standard deviation? And more importantly, does the precision assume a perfect operator (so the ...
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1answer
628 views

How/where to take moments to solve a static equilibrium equation

A 200×250 mm panel of mass 20 kg is supported by hinges along edge AB. Cable CDE is attached to the panel at C, passes over a small pulley at D, and supports a cylinder of mass m. Neglect the effect ...
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1answer
369 views

Simple statics vector analysis problem [closed]

I know the stack exchange does not help on hw problems, but please understand that I am just self learning these topics, I'm not in a class, and I'm using my dads old engineering mechanics book... Now ...
2
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1answer
207 views

Equilibrium of rigid bodies

I wanted to evaluate the safety of a walking aid device (walker). For example, if the way it is constructed and whenever I handle it, there are no risk of rotation, around its center of mass, turning ...
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3answers
3k views

Method of Calculating pressure of failure in a cylindrical container?

Is there a formula or method to calculate the pressure of failure of a cylindrical container of known material, thickness, and size?
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1answer
3k views

The boundary condition(s) for a continuous beam

I have a continuous beam across a center column (not sure whether I've draw it correctly or not) The Displacement and force diagram is as shown: The first diagram is the bending moment, second the ...
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1answer
16k views

How much weight can an aluminum tube beam support?

I'm building a set of monkey bars for my kids and want to use aluminum tubing (6061 T6) for the rungs. The tubes will be 3 feet long and 1 inch outside diameter. Supported on both ends with a circular ...
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3answers
15k views

Maximum Shear stress in Beams

I understand that for a rectangular c-s the shear stress distribution is parabolic and the max shear stress occurs at the neutral axis and has a value of 1.5V/A. Where V is the 'applied shear force' ...
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1answer
140 views

Finding the components of a vector along two other vectors

Using only the diagram above (Not using the questions in the diagram), i am asked to find the components of F2 along F1 and F3. I am having trouble with this question. I can easily resolve any of ...