Falling Definition and 1000 Threads

Hello I'm tasked to evaluate the roof of a small power station situated beneath a rather high tower in an alpine landscape, by means of FEA. One requirement is that the roof shall endure chunks of ice falling on it. Problem is, I am stumped as how to find the loads. The Eurocode norms I am...

F=ma eg, a static bag of a 1kg weight has a force on the table of .98N. if it were to fall, would its force hitting the ground be the sum of the standard g of 9.8m/s+ 9.8t? or do you scrap that idea and use K.E. instead? and also, if it reaches terminal velocity and has an acceleration of 0...

A one meter chain that weighs one Newton sits on a flat horizontal table that is one meter from the floor. The coefficient of friction between the chain and table is 0.15. How much of the chain can dangle off the table until the chain pulls itself onto the floor?If it starts to fall from this...

Consider the Schwarzschild line element for radial motion only: c^2 d\tau^2 = \left(1-\frac{2GM}{rc^2}\right) c^2 dt^2 - \frac{dr^2}{ \left(1-\frac{2GM}{rc^2}\right)} Solve for d\tau^2/dt^2: \frac{d\tau^2}{dt^2} = \left(1-\frac{2GM}{rc^2}\right) - \frac{dr^2/dt^2}{...

Ok, so I watched a horror movie recently and they did the whole drop a rock down a cavern and see how long it took to hit the bottom. Couldn't you find the approximate distance through this? Not just a guess like "Oh that took a little bit so it's waaaay down there". If two objects...

When there is a lamp on a wall and the light from the lamp falls on the wall, we notice that the shape formed by the light is a hyperbola. I would like to know what the explanation for this is. Also, when you have a convex lens and you kee it flat on a horizontal surface, and sunlight falls at...

A helicopter is ascending vertically with a velocity of 12.5ms^-1. At a height of 120m above the ground a package is dropped out the door. How long does it take for the package to reach the ground ?. The attempt at a solution I know U = 12.5ms A = -9.8ms V = 0ms S = 120m...

Homework Statement Hello, I need help with a simple task. I want to calculate the force which appears when a mass falls on the floor without bouncing. I have modeled a bicycle crankarm, and I want to calculate the stress in it. In order to do that I need a force. So I want to know the...

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What is the correct way to calculate the probability of a given number of consecutive data points forming a saw-tooth pattern? The magnitudes of the rise or fall (the size of the moutain and valleys) are not material. The only requirement is that each set of three consecutive data points...

It is known since Hawking that an observer "a rest" at some far distance of a black hole sees a thermal radiation emitted by the black hole. The mass of the black hole diminishes while it emmits the thermal flow of particles. For a free falling observer there is no thermal radiation. So, for...

Homework Statement A tube is mounted on a flat cart which is in uniform motion on a horizontal plan. How must the tube be orientated on the car in order for rain drops, falling vertically, to miss hitting the walls when falling inside the tube? The motion of the rain drops is assumed uniform...

First Post..hopefully of many! I have to work out the minimum distance a 5.6KG object can fall vertically to 'acheive a force' of 12KG when the object hits the ground. I have no other information and really need some help! P.S. I am not a scientist, simply a confused manager needing a...

A long, thin rod of mass 9.65 kg and length 10.18 cm is standing stright up on a table. Its lower end rotates on a frictionless pivot. A very slight push causes the rod to fall over. What is the speed of the tip of the rod as it hits table? What is speed of center of mass of rod? 1/2 m...

'speed' of sound vs. 'feel' of sound? (e.g. subwoofer, tree falling, etc.) When bass plays from a subwoofer, a tree falls, a bomb explodes or something similar there's a very real physical sensation that accompanies the sound. My mind is most curious to know if these travel at the exact same...

Homework Statement Alright, this one's been bothering me. An engineer is designing a spring to be placed at the bottom of an elevator shaft. If the elevator cable should break when the elevator is at a height h above the top of the spring, calculate the value that the spring stiffness...

What's the best way to capture the energy produced by a falling object, and then use that energy to produce electricity for example ? Like for instance, I've been thinking of a kind of water mill where it would be an object falling on the blades instead of water, therefore making the mill...

I was wondering how to calculate the drift of an object that is falling though air. If I know the mass, air density, and velocity of an object that is falling how can I calculate its movement off the center of he drop point. I.E if you looking down on a grid with x and y on the side how many x...

Homework Statement Find the velocity of a 180 lb object falling from a state of rest from 5 ft, 15 ft, 25 ft, and 45 ft Homework Equations using the formula f=mg-Kv2, where g is the acceleration due to gravity, m the mass of the body, v its velocity. The terminal velocity is 120mph...

I understand that anything falling into black hole would appear to take forever to cross the event horizon relative to an observer at a distance. But what if you were hovering right above the event horizon and you saw someone fall in? Would they still appear to be frozen in time? If so what...

Hey everyone Homework Statement Im trying to calculate the force encountered by an object falling due to gravity that is caught by a rope. Obviously F=ma and since mass is constant I need to find the rate of deceleration. I've tried to using the equation v^2 = u^2 +2ax as v = 0 and u...

Homework Statement A raindrop is falling through a cloud, collecting water as it falls. If the raindrop has mass m and velocity v, show that mg = vdm/dt +mdv/dt. Assume that the drop remains spherical and that the rate of accretion is proportional to the cross-sectional area of the drop...

Ok, just a few minutes back, a tic-tac slipped from my hand and fell to the ground. The second bounce was to a lower height than the first (which is expected because e*<1) but then as it took the third bounce, it rose to a height higher than the one reached by it than in the second bounce. I...

Hey all, Just a quick overview of myself, I have recently started rock climbing (6 month) and I'm finding myself becoming more curious about the technical equipment involved. I'm finding it hard to word the questions I'm trying to find the answers too. So I'm going to try and I'm...

The question is rather old but I am not sure if we have a final conclusive answer (I was not able to figure it out for myself, nor have I found consensus in the literature) 1) do free-falling charges in a static gravitational field radiate? 2) do charges at rest in a static gravitational...

Homework Statement A car and pulley system are setup as shown. Find the acceleration of the car. The car wheels have a friction coefficient of 0.15. The car has a mass of 0.05 kg while the block has a mass of 0.02 kg. http://sadpanda.us/images/836771-GBD7SB9.jpg *sorry if the picture is bad I...

Homework Statement A ball of mass 0.5 kg rolls off a table 4 metres above the ground with a speed of 4 ms^-1. a) what is the kinetic energy of the ball when it strikes the ground. b) what is the kinetic energy of the ball just before it strikes the ground c) what is the speed of the...

Homework Statement How would the graph of position vs. time for a single cone change under each of the following conditions? 1)the cone's mass was increased but its shape was kept the same. 2)the cone's mass was kept the same but its diameter was increased. 3)the cone fell through...

Hey guys, I'm a new guy in this forum. I've been visiting it for 1 year actually but never decided to register and so I did. I am having a presentation on black holes at school and I want some clariffication of what's going on when falling into a black hole. Well let's assume that an...

A sheet of plywood is held with one edge resting on the floor, as shown in the figure below. The plywood surface initially makes a small angle, Θ, to the floor. At time t=0 the held edge is released and the plywood pivots about the edge on the floor as it falls down. It is observed that the...

Hi I am trying to understand the effect of dropping a magnet through a single coil of wire. If there is one turn of wire, connected to a resistor, and a magnet with known mass and flux density is dropped vertically through the coil, a current will be induced in the coil. The forces acting...

Homework Statement two balls are thrown from a cliff. one is thrown directly up, the other directly down, each with the same initial speed, and both hit the ground below the cliff. which ball hits the ground at the greater speed? The Attempt at a Solution I know the answer is that they...

Homework Statement A bar magnet is dropped through a horizontal coil as shown below. An EMF is induced in the coil with the resultant voltage shown on the graph. Explain the shape of the graph, in particular the differences in the regions marked as A, B and C. Homework Equations...

In a free falling elevator, can you jump, my question is as simple as that, my teacher said you can't (due to newtowns 3rd law since there would be nothing with which I could cause the reaction of jumping) but still can you ?

Any idea where these space balls came from? Its speculated that several such balls have dropped in southern Africa, Australia and Latin America in the past 20 years.

I have two 2 rigid bodies with masses m1 and m2 and Moments of Inertia I1 and I2, they are connected by a free rotational joint at some point, their coms lie at c1 and c2. There's gravity. In the beginning both have some angular velocity \omega_i Questions: - Total angular momentum of the...

1. A uniform rigid rod of length L and mass M is attached to a frictionless pivot point at one end. The rod is initially held completely horizontal and is released from rest. What is the linear and angular velocities at the instant the rod is in the vertical position?2. -ΔU = ΔK 3. -ΔU =...

How to calculate the velocity of a object falling due to gravity through a pipe (vertical) where the fluid is flowing in upward direction? Please ignore the frictional force & just consider F net = F (gravity) - F (drag) - F (force the fluid exerting on the object during upward flow) -...

Homework Statement this comes from griffiths 7.46/11 A square wire loop is placed so that its top portion is in a uniform magnetic field. It is then allowed to fall under gravity. We then repeat this experiment but instead rotate the loop 45° so that it is a diamond. Which orientation...

hi, i've got a little complicated question, let's see if i can formulate it in an understandable way. imagine there's an (ideal) pencil, standing on its (ideal) tip. if it would stand at 90degree to the (ideal) table, it would never fall. now the question is, if it doesn't stand at...

These damn shows on the Science Channel seem to raise more questions for me than they answer, and maybe I'm understanding this wrong but here we go... If I were an unfortunate soul who fell into a black hole, the show claims that I will not feel a thing as I pass through the event horizon...

Hi I'm wondering, if I had a mass of 10kg and I dropped it 10 metres, how would I work out how much force is exerted on a rope? Thanks David.

I think we're all familliar with the old "What if you fell into a black hole?" Event horizons, time dilation (I think is the right term), and spagettification. There is however one thing these thought experiments never seem to cover that I'm really curious about. As I understand this...

"2 spades of the same type are dropped form the same height into the same patch of soil. why does the heavier spade have a lower acceleration in the soil than the lighter spade?"

Recently, there has been an argument of whether or not you would sink if you were unlucky enough to fall into a volcano. The proponents of this argument focus their attention on the water/magma density difference. Since the human body consists of 60-70% water, and water is less dense than...

Homework Statement A 25 kg wheel has a radius of 40cm and turns freely on a horizontal axis. The radius of gyration is 30cm. A 1.2 kg mass hangs at the end of a cord that is wound around the rim of the wheel. This mass falls and causes the wheel to rotate. Find the acceleration of the...

Homework Statement k: constant v: velocity m: mass g: gravity Homework Equations Vt= √(2mg/CρA) F=ma The Attempt at a Solution part a. part b. I do not know if i am doing this right and i do not understand how to do part c. If you know how to do this please explain

Homework Statement One pulley, on one side we have a block with mass m. On the other side we have a cylinder with mass m. Cylinder (radius R) has unlimited string (massless, negligible thickness, no slippage) So you can imagine two blocks falling as more string unravels from the...

Ok. I'm not sure if this belongs in this section. This is a problem relying on physics 1 concepts, but I do believe it requires MultiV Calc (which I haven't taken) to solve. 1. The problem How long would it take a particle of distance D away from the center of the Earth to fall to the surface...

Homework Statement Today I had a physics midterm and one question that was on it is really bugging me and my friend. We'd really appreciate it if one of the experts here could give us their spin on it (I know...bad pun ;)). The question is: A yo-yo (a solid cylinder with a string...