Dynamics Definition and 1000 Threads

HI All, I have been out of education a long time and am now back at college. One of my modules is Fluid Dynamics and I am beginning to struggle with the basics and could really use your help. I have attached a snip from one of the example questions below given to me by my lecturer. For part...

I am confused with this concept. So if a system possesses multiple possible eigenfrequencies (and therefore modes), how does the system "know" which eigenfrequency will it want to vibrate on? Does that depend on the initial condition you give the system? Is there any mathematical relation...

Homework Statement As you'll know, the driving force for a circular movement is a centripetal force. But wat is the dynamics for a spiral movement, i.e. an increasing circular movement? And how can I produce it, let's say for a little spherical object, in real life? The Attempt at a Solution I...

Homework Statement The figure below shows the speed of a person's body as he does a chin-up. Assume the motion is vertical and the mass of the person's body is 72.7 kg. Determine the force exerted by the chin-up bar on his body at the following times. My answers: Homework Equations F = ma...

Homework Statement A flat cushion of mass m is released from rest at the corner of the roof of a building, at height h. A wind blowing along the side of the building exerts a constant horizontal force of magnitude F on the cushion as it drops as shown in the figure below. The air exerts no...

Homework Statement Two pucks (5 kg each) made of Teflon are on a long table, also made of Teflon. Puck A is sitting at rest on the left end of the table. Puck B is 15 m away at the right hand end of the table, and is travelling toward Puck A with an initial speed of 0.5 m/s. A person on the...

Homework Statement Two pucks (5 kg each) made of Teflon are on a long table, also made of Teflon. Puck A is sitting at rest on the left end of the table. Puck B is 15 m away at the right hand end of the table, and is travelling toward Puck A with an initial speed of 0.5 m/s. A person on the...

Homework Statement Homework Equations y1+P1/##\gamma##+##\alpha##v12/2g = y2+P2/##\gamma##+##\alpha##v22/2g + hL The Attempt at a Solution so it gives me pressure at p2 but not p1. I tried using Bernoulli's equation to find p1 i did plugged into energy equation above and got an answer but...

Hello Everbody In Sci Shows newest video they take about alternates to Dark Matter and one of these is Modified Newtonian dynamicse. The guy states that there were two teams one proved that it existed and the other did the the opposite. My question is why they can't and didn't compare there...

The spatial orientation of the double slit setup be so that the screen extends in a plane ##x = constant##, while the entire apparatus sits on a ray perpendicular to the screen (of course, the slits sit and extend a bit off this ray). My questions are about the dynamics in x-direction if only a...

I am a high school student interested in fluid dynamics, especially the Physics of ocean waves. So I'm hoping to do a science fair project about the Physics of sea waves, maybe for local science fair, or if it's really good, ISEF. The trouble is, I don't know what to do, especially because the...

Following Frekel-Smit book: https://www.amazon.it/dp/0122673514/ I am trying to write a program based on the algorithms 3,4,5 and 6 in the book. I use a cutted-shifted Lennard Jones potential, with cutoff radius at 2σ. #include <iostream> #include <cstdlib> #include <cmath> #include<fstream>...

Homework Statement A formula has been determined: d=l+h+ (l(SRT(m(m+150))+m)/75), where d is the depth jumped to, l is the length of the rope, h is the height of the jumper and m is the mass of the person. The question is: At present, the model does not include air resistance. Show and discuss...

Homework Statement In the diagram, m1 has a mass of 47 kg and m2 has a mass of 35 kg. The coefficients of friction between m1 and the surface of the inclined plane are µs = 0.42 and µk = 0.19. (a) If the masses are held in place and then released, will they start to move? (b) If the answer...

We have a cube on an inclined plane. The tipping condition is the presence of an unbalanced torque relative to the center of mass (contributing forces are: the normal force and the force of friction). However, is this conditions equivalent to the previous one: The line of action of the force of...

What's the minimal angle of a ramp such that a cube with side 10 cm placed on it will tip over? The coefficient of friction between the cube and the ramp is 0.6. I have given it some thought and I have come to certain conclusions: I think that the cube will tip over once the force of gravity...

We have two identical balls sitting at the same height. One of them is released without applying any force (it falls freely) and the other one is given a non-zero horizontal velocity. Which of them will hit the ground first? The force of air resistance is proportional to the square of the...

Let's say that we have a bicycle wheel with radius $R = 25 cm$ and mass $m = 1 kg$. We spin the wheel in air so, that the tread is moving at the speed of $v_o = 50 km / h$. Then, we let it roll on asphalt, given the coefficient of static friction: $f_s = 0.9$ and kinetic friction: $f_k = 0.7$...

Let's say that we have two guys, each weighs 50 kg. They are pulling a piece of against each other as hard as they can. The tension of the rope will therefore be the force of friction acting on each of them (the same magnitude). Now, let's say that a third person joins the party and grabs the...

Homework Statement Whats is the final speed of the second box(mass = 1kg) when the first one (mass = 5 kg) has descended a distance equal to 0.6 meters in the rough ramp inclined 60° respect the x axis. Consider the spring is compressed a length x = 0.2 meters. The second box is tied to the...

Homework Statement Imagine exactly same two bodies (same mass, same surface/friction etc) are attached with a string/spring and they suddenly start pulling towards each other with equal force. I can imagine they will move towards the center. If there is a chain (with defined number; not...

I need to scale my solar system model and it's not working. I'm making an augmented reality app that shows a sample solar system rotating. It works great! (Thanks to this $7 program https://assetstore.unity.com/packages/tools/physics/gravity-and-orbits-solar-system-105300 . The Unity engine...

Hi, I am trying to gain insight into using stationary vs. rotating coordinate frames for natural frequency calculations. I have seen many FE codes suggest that critical frequencies can be calculated differently in rotating and inertial frames, so i wanted to do a 1D calc to see for myself how...

I'm new to this forum, so please forgive if this is posted in the wrong thread and redirect me. I teach high school Physics and we just got a large unexpected grant which means I can finally buy a set of dynamics cart and track systems for my classroom. I am trying to decide between buying...

Homework Statement Viewing a solution on the internet to this question, the free body diagram is drawn as: The forces here are then used to solve for ##F_D## and this is given as the answer to "the force which the bar exerts on the link at D". I'm just confused as to why there is no...

Homework Statement [/B] There are two blocks that have equal mass m, they are connected by a spring (with a coefficient of elasticity k) that has length l0. Instantly on the left block a force F begins to act. What will be the min. and max. length of this spring during this movement. There...

Homework Statement An object is placed on a slope with initial velocity v=0m/s. Angle of the slope is 30 degrees and the coefficient of friction (or friction factor, not sure how it's said in English) is given as u=0.1*(x/m) where x is the path traversed and m is the mass of the object. After...

Homework Statement so I was going over my notes on classical mechanics and just started to review rotation matrices which is the first topic the book starts with. On page 3, I've uploaded the page here The rotation matrix associated with 1.2a and 1.2b is \begin{pmatrix} \cos\theta &...

Homework Statement The coefficient of kinetic friction between a 3.5kg bowling ball and the ice on a frozen lake is very small: μ= 0.02. If the ball is bowled on the ice with an initial velocity of 16.5ms^-1, how far will it travel before friction brings it to rest? Homework Equations Fn=mg...

Imagine such situation: A bus is moving at constant speed, a man is standing on the bus and is not holding to anything - he is simply standing. Now, the bus starts breaking with constant negative acceleration and so the man will change his relative position due to the force of inertia. Now...

Homework Statement A car is traveling up a slope. Given that a(t) is constant at 1m/s^2, find the expression of motor power in time. Assuming that the maximum power of the car is 215kW, for how long can the car maintain such an acceleration? Mass of car (m) = 2000 kg The hill has a constant...

Homework Statement Homework Equations The Attempt at a Solution

Imagine that you are using an elevator and - due to some cause - all of the cables supporting it cracked and the brakes were not engaged - the elevator is in a free fall. Now, would it be technically possible to jump in that elevator? Jumping requires the force of reaction of the ground, this...

Homework Statement A child of an Eskimo decided to slide down an igloo. The igloo looks like a hemisphere with radius R. When will the child fall off the slide? Homework Equations See belowThe Attempt at a Solution There are only two forces acting on the child - the force of gravity and the...

Homework Statement A loaded railroad car is rolling at a constant velocity when it couples with a spring and dashpot bumber system. After the coupling, the motion of the car is defined by the relation ##x = 60e^{-4.8t} sin16t##, where x and t are expressed in millimeters and seconds...

I am currently solving a problem where I need to find the gravity in the ISS (distance 400km from Earth with Radius 6371km). I am using the formula g=GM/R^2 . One way to solve it would be to find GM by multiplying g(which is 9.81) and R^2 (which is known) and then to use it in GM/(R+400)^2 and...

Homework Statement Homework Equations because their is steady flow we only care about mass flow flux meaning m1vout - m2vout m = ##\rho##Av i know that m1 = m2 + m3 since there are no dimensions I am assuming that areas are the same everywhere, density does not change therefore velocities...

Hi all, I'd like to confirm my understanding on some things regarding pressure losses in a branched pipe for a project. Referring to the picture below I grabbed off from the net. (assume no elevation chan Would appreciate if someone can correct me if I'm wrong anywhere. 1) Total pressure...

Homework Statement Homework Equations Moment of inertia Torque Angular momentum The Attempt at a Solution I think I can understand the physics of the situation. There will be a torque on the bus due to gravity while the back of it remains in contact with the cliff and it will start to rotate...

Consider a simple single degree-of-freedom (SDOF) spring-mass-dashpot dynamic system with spring rate k, mass m, and viscous damping coefficient c. Dimension x is the absolute displacement of the mass. The base input translation is y. A dot notation indicates differentiation with respect to...

Homework Statement If a car has an emergency breaking system that can be pulled by the driver, which will decelerate the car at a rate of -4.0m/s^2, how long does the driver have to react before it is too late. (If she enters the intersection at all is it too late?) Homework Equations No idea...

Hello! Would love a quick explanation of these two exercises :) 1. Homework Statement 1) Find objects acceleration, when mass is 200kg and it is being pulled on a horizontal plane with a force of 2000N. How much work is done on 400m road? 2) An object fell from 200m. How much of its energy...

I do know that supposedly the time-evolution operator is unitary. At the same time, I have come across a peculiar case during a calculation. Suppose that I have a basis that is complete (and not overcomplete), and element of Hilbert-space at t=0. For some reason, the solution of the...

((((As a correction dissipation function in picture should have square of divergence of U)))) Hi, first of all I am aware that we have to discretize the non linear navier stokes equations to reach the almost exact solution, and pressure based or density based algorithms are deployed for that...

Homework Statement Homework Equations RKE = .5iw^2 TKE = .5mv^2 U = mgh The Attempt at a Solution is my setup correct? mgh = RKE +TKE mgh = .5Iw^2 + .5mv^2 do i just total up the RKE and TKE for both the objects?[/B]

Hi folks, This week I have a question about rigid body dynamics analyses in CAE. This is in relation to the final year project of my degree. Over the past few months I've been working with AnSys 18.1 for FEA however, I've reserved AnSys exclusively for static analyses. For rigid body dynamics...

Homework Statement A block of mass m is placed on a rough wedge inclined at an angle α to the horizontal, a distance d up the slope from the bottom of the wedge. The coefficient of kinetic friction between the block and wedge is given by µ_0x/d, where x is the distance down the slope from the...

Homework Statement In the figure there are a block 1 of mass ##M##, a pulley (disk) of mass ##M## and radius ##R## and a second block of mass ##2M## on an inclined plane with an angle ##\alpha## with respect to the horizontal. On this plane the static friction is ##\mu##. The wire does NOT slip...

Please tell me which one is wrong! When I put a mass M on one end of a spring!

Dear, Everyone I am a new member here, nice to meet you.. First, I want to introduce my self, I am a master student of physics and I am studying CFD right now. It's a new topic for me and I will also do my research about simulation of fluid dynamics related to CFD. Actually, I got this topic...