Dynamics Definition and 1000 Threads

Hi everyone. I am a little desperated cause my exam is on monday and still much stuff to do. I don't get when I am supposed to use/consider radial and tranversal forces. Most excercises say "it rotates on the horizontal or vertical" I guess this is the info that tells me if there is...

Hello, I'm trying to simulate disc galaxy dynamics with a nbody code. The main problem is to get good initial values (positions and velocities of each star) in order to reproduce the experimental dynamics. For the positions, I began by generating a gaussian distribution of stars on 0x...

Homework Statement Please click on the link for the question. http://i1154.photobucket.com/albums/p526/cathy446/physicsquestion_zps49e16ab1.jpg Assume that air spreads out after coming out from the tube at 2. The speed over tube 1 is almost zero. Homework Equations Knowledge problem on...

Hey Guys, I have tough dynamics question. I wasn't sure if this is the best place to post it, so if it isn't please let me know. I thought it might be because I couldn't find anything about it anywhere. So here goes. If one had 10 inch long hose, 1" in diameter, filled with some incompressible...

1D Dynamics Problem! Homework Statement A car of mass 1100kg is traveling at a constant velocity of 60 km/hr, east. The coefficient of friction between the tires and the road is 0.45. The driver of the car sees the traffic light in front turning red and steps on the brake, only to find that...

Homework Statement At the instant shown, point P on the cable has a velocity 12 m/s, which is increasing at the rate of 6m/s^2. Determine the power input of motor M at this instant if it operates with an efficiency of 0.8. The mass of the block A is 50kg. I've attached a picture of the...

Homework Statement At the instant shown, point P on the cable has a velocity 12 m/s, which is increasing at the rate of 6m/s^2. Determine the power input of motor M at this instant if it operates with an efficiency of 0.8. The mass of the block A is 50kg. I've attached a picture of the...

Hello, this is not homework, I am trying to derive some physics results using intuition, I am currently looking at some fluid dynamics problems. Consider a water droplet on a frictionless horizontal plane, subject to gravity. The cross-section of the droplet would look something like this...

Homework Statement From the edge of a cliff, two stones are thrown at the same time, one vertically upwards and the other vertically downwards with the same velocity of 20 m/s. The second stone reaches the ground in 5 s. How long will the first stone be in air? Also find the height of the...

Why is ft (the force due to the friction between the cylinder and the ramp) not included in the equation of motion?

Hi All, I was wondering if anyone could post some videos or some websites where I can read about Dynamics required for Mechanical Engineering i.e. related to vectors , how to add vectors , how to find the resultant. I searched YouTube but I am not really getting any good responses. I am a...

Hi everyone! I saw in an old exam of physics : "Write and comment the second law of dynamics." And i was thinking, I know a lot about it and if i had to answer it i would have made some examples, but when he asks me to comment it ? What should i have to say ? In sense, what do you think are...

The Problem. 12-101 Hibbler dynamics 13th edition. It is observed that the skier leaves the ramp A at an angle θA=15 degrees with the horizontal. if he strikes the ground at B, deterime his initial speed VA and the speed at which he strikes the ground (at B)...

Hello, I found this problem while preparing for the qualifying exams and thought I would tackle it. I have no idea if it is correct, but I would like someone to tell me if there is an easier way to solve this than I used. Perhaps some Lagrangian or Hamiltonian approach? Thanks. The...

Good morning all. I wondered if anyone could assist me with the following dynamics problem. The question is copied from Burdens Dynamics and Mechanical Sciece Self Study. Question) Three balls of mass 2kg each, have a coefficient of restitution of k = 0.85. Ball A is released at a height of...

Okay I have done it, but have a feeling that there's something wrong. I don't have the solution/answer so it will be great if someone can help me check. more of part 2 (which leads to part 3) Homework Statement a body of mass 6.0kg and density 450kg/m^3 is dropped from rest at a height of...

Homework Statement A uniform sign is nailed into a wall at its top two corners. The nail on the upper-right corner breaks, and the sign begins to rotate about the remaining nail in the upper-left corner. The mass of the sign is 69 kg, L (length) = 1.6 m, H (height) = 2.2 m, and the moment of...

Homework Statement A thin uniform rod is attached to an axis through its midpoint. The axis is standing on a disk rotating with constant angular speed \Omega about its symmetry axis. The rod's midpoint is located directly above the rotational axis of the disk. Let \theta denote the rod's...

For a unit mass sliding down the stationary curve y = f(x) at the point (x, y), we can consider our mass to be sliding down a stationary inclined plane which is tangential to the curve at the point (x, y). The slope of this inclined plane is thus \frac{dy}{dx}(x). For the remainder of this...

Hello all, Semester has just started and i am dong a 4th year dynamics unit, so i am reviewing the previous years unit which was a pre-requisite for the unit i am currently doing. I have come across a rather difficult dynamics problem that was given as a challenge question at the beginning of...

Homework Statement You are working for the Peace Corps in a developing country. Your job is to design a simple, but accurate scale for weighing bulk materials such as food and construction materials. A possible idea consists of a loading platform, D, that is supported by cable AB, where end...

So I've been busting my head for the past 2 days trying to figure out what I was doing wrong and I just can't. I have a whole bunch of these types of questions and can't solve any of them. My own equations and reasoning make sense to "me" but don't lead me to the right answer. I am positive I'm...

Hello again forum :smile: I am still studying for that unit test and am still having problems with dynamics... I've attached the problem with the calculations/solutions. Basically, I don't understand why I'm getting the wrong answer. Probably b/c idk what the heck I'm doing :eek: Homework...

Hi everyone, I'm new to forum and am a 3rd year university student who has never taken physics until now.. I'm currently studying for a dynamics unit test and came upon this question... Homework Statement A car whose brakes are locked skids to a stop in 70m from an initial velocity of...

In my course they're using the equality U = \frac{p}{\alpha \rho} with alpha some constant (U = internal energy per mass, p = pressure, rho = density). They explicitly derive it for an ideal gas yet later apply it to a liquid (in the context of deriving the Navier-Stokes energy equation). Seems...

Homework Statement See attachment "problem" Homework Equations Euler's laws of motion (moment equations), work and energy equations The Attempt at a Solution See attachment "work" I did the work for (1) and (2). I end up with two equations: the first is the tension T, the second...

It is said that the stress tensor \mathbf T for a fluid at rest is diagonal. Why is this? The fact that the fluid is at rest means there is no net force, i.e. the body and surface forces cancel each other: 0 = \mathbf F + \nabla \cdot \mathbf T, but from this condition is does not follow...

So Reynold's transport theorem states that \frac{\mathrm d}{\mathrm d t} \int_{V(t)} f \; \mathrm d V = \int_{V(t)} \partial_t f \; \mathrm d V + \int_{V(t)} \nabla \cdot \left( f \mathbf v \right) \; \mathrm d V. Now I would expect (on basis of conceptual reasoning) that if I were to apply...

Hi I'm creating a hamster cage for better ventilation(circulation) without too much flow.(draft) How would I work out mathematically the air flow going into a plastic box. The flow rate etc.. The plastic box will be inside a normal home. Things I want to know and improve The overall...

Hey Guys, I continue to get mixed messages about the nature of electron behaviour during the double slit experiment. I have heard the term observation used to describe an interaction with the electron (Obviously necessitating a change in it's behaviour to facilitate the ballistic outcome)...

A car of mass 900 kg is towing a trailer of mass 300 kg along a straight horizontal road. The car and the trailer are connected by a light inextensible tow-bar and when the speed of the car is 20m s−1the brakes are applied. This produces a braking force of 2400 N. Find a the deceleration of...

Fluid dynamics -- Where to post questions? Is this the place to post to discuss fluid dynamics?

Hi, I have a simple question and shall be grateful if helped. See the attached word document.I have been reading the derivation of the consistent mass matrix- for the axially loaded bar.My question is: 1)While formng the equation 10.51 (referring figure 10.7), the author considers...

Sorry guys, As I understand there is no introduction topic or what so ever so I'll do it here. Don't want to burst in without introducing myself. Hi I'm Andrew from the netherlands and during my websearch for a solution to my problem came across this forum. After finishing my mechanical...

Hello everyone! I have constructed a model of a silicon crystal, consisting of 64 atoms, for my various needs of testing physical phenomena in that substance(Silicon). At present, rather annoyingly, I am still stuck at the basic operational level, that is, calibrating the system to an expected...

(First of all apologies for the long wall of text) I am to study BRST transformations, for which I'm currently trying to understand constrained Hamiltonian dynamics to treat systems with singular Lagrangians. The crude recipe followed is Lagrangian -> Hamiltonian -> Dirac brackets and their...

Homework Statement How long would it take for the block to travel 10m starting from zero velocity? (i.e. T =?) (Look the the attached picture for the block and the position of it on the plane at 45 degree and 10 m from ground with the same slope) Theta = 45 degrees m = 1.0 kg f = 0.3...

under what conditions can a rigid body collision problem be solved using a system approach, (i.e by using the conservation of angular momentum of the two rigid bodies about some point) the equation M=d[H]/dt is only valid when M and H are taken about a point fixed in a massless extension of a...

I have some car engine related questions, but basically just physics. -Do different specific heat capacities have anything to do with how certain materials resist heat? I know that on some engine compartments there is gold wrapping because it resists heat best, but it has a low specific...

A perfectly rough rod is gently placed with one end upon another rod of equal mass and in the same vertical plane, moving with the velocity √2gc on a smooth table. If the initial inclination of the first rod to the horizon be α, and its length 2a, shew that it will just rise to a vertical...

Fluid Dynamics help?? Homework Statement A boiler is supplied with water at a rate of 0.5 kg/s through a pipe of diameter 80mm a) Calculate the velocity of the water in the pipe b) The velocity of the water just before it enters the boiler through a pipe and is raised by a means of a...

Homework Statement A man acts as as a human cannonball. When the cannon is fired, he has a velocity of 18ft/s. How far will the man have traveled when his acceleration is 0? When will this occur? Neglect friction. Also given is: Man is 120 lb-m Homework Equations kinematics...

Homework Statement Water flows down a channel whose floor is porous, so that water seeps out of the bottom of the channel at a speed v, where v is constant and much less than the flow speed, U, along the surface of the channel. The seepage rate is slow so that H may be regarded as constant...

Homework Statement A wagon having a total mass (including its wheels) of 1000 kg, has four wheels each of mass 100 kg and each having a radius of 0.5 m and a radius of gyration of 0.45 m. The wagon starts from rest at the top of an incline of 1 in 10 (sine). If there is a resistance to...

Homework Statement A particle of mass 3.2kg is moving due west with a velocity of 6m/s. Another particle of mass 1.6kg is moving due north with a velocity of 5.0m/s. The two particles are interacting. After 2s the first particle is moving in the direction N 30° E with a velocity of 3m/s...

Homework Statement See attachment "problem" Homework Equations The Attempt at a Solution See attachment "work" and "answer" I got 0.92, but the book gives 1.73. Something went wrong, but I can't find it.

If : The total energy of a falling rock = G.P.E. (mass x gravity x height) + K.E. (0.5 x mass velocity^2) But if a rock reaches terminal velocity (i.e velocity remains the same) but height keep decreasing, then surely Kinetic energy is remaining constant and Gravitational potential energy is...

Homework Statement A duct of length 5 m at 38 Degrees inclination to horizon with a cross section dimensions of 0.3 m X 0.4 m is carrying 2 kg/s of a heavy gas at 10C and 1.2 bars and delivers the gas flow at 50C at the end of the duct to a horizontal pipe section. i) Calculate changes to...

hi community, In general I would like to know the what's the general way of solving the moderate or large-scale eigenvalue or algorithms in structural dynmics. The simple motion equation is as follow. M*d2X(t)/dt2+C*dX(t)/dt+K*X(t) = F(t). The bolded expressions are known before the...

1. A 5 kg board is arranged between 2 sawhorses (at right). If the board is in static equilibrium, what is the normal force on the board from sawhorse 2. Link for the picture the question is referring to. h.ttp://i.imgur.com/nBC6A.jpg a. F2,normal = 0 N b. F2,normal = 49.0 N c...