Falling Definition and 1000 Threads

In the following link is a slow motion video of a maple tree seed falling (you have to wait till the 7th second). From the Wiki article on Action http://en.wikipedia.org/wiki/Action_%28physics%29 "In physics, action is an attribute of the dynamics of a physical system. It is a mathematical...

Homework Statement A bottle is filled with water and turned over so it is 90° to the horizontal, the cap is then removed and the water will pour out. At what rate will the water accelerate? (Ignore friction with air) A. Less than g B. equal to g C. more than g Homework Equations...

I have been thinking about how to come up with a function of time for the n-body problem. Later I found that there still is no function of time known for the n-body problem, but I am still not sure where the brick wall for everyone is because I am quite sure my understanding has hit from very...

Hello. Recently I have been inspired by the classic "drop a NdFeB magnet down a copper tube" demonstration, and I have been thinking about a superconductor falling in an ambient magnetic field. I want to determine the terminal velocity, if one exists. Now, I'm interested only in the effect...

Homework Statement The height of which it will be dropped 5.1816m, then the mass is 0.057kg. and the gravity is 9.8m/s^2 .What is the force downward? what's the net force and what's the up force? and what's the time to hit the ground? Homework Equations Fg=m*g The Attempt at a...

Homework Statement The gravitational pull of the Earth on an object is inversely proportional to the square of the distance of the object from the center of the earth. At the Earth's surface this force is equal to the object's normal weight mg, where g = 9.8m/s^2, and at large distances, the...

Homework Statement While exploring the canopy of the rainforest in equatorial South America, Anastasia falls from a branch 39.0 meters high. Exactly 0.8 seconds later Joe falls from the same branch. How high above the ground is Joe when Anastasia splats into the mud below? (the mud is very...

Homework Statement Hi everyone! This is not actually a homework problem, but I thought it was similar to one so I am putting it here. Basically I was watching this youtube video of a falling slinky and I decided I wanted to try modelling it with physical equations: The problem I have...

I made an animation to explain how cats can initiate rotation and turn around during free fall, without violating the conservation of angular momentum: https://www.youtube.com/watch?v=yGusK69XVlk Some footage of real cats: https://www.youtube.com/watch?v=Ua4Gh_4XdwQ...

A camera falling from a blimb... pleasezzz help (part 1 of 2) A camera falls from a blimp that is 349 m above the ground and rising at a speed of 17.2 m/s. Find the maximum height reached by the camera with respect to the ground. The acceleration of gravity is 9.8 m/s^2 Answer in units of m...

Homework Statement You drop a baseball from the roof of a tall building. As the ball falls, the air exerts a drag force proportional to the square of the ball's speed (f=Dv2). (a) In a diagram, show the direction of motion and indicate, with the aid of vectors, all the forces acting on the...

Homework Statement The problem is: A bullet shot vertically upward leaves the gun at a velocity of 655 m/s. How far above the muzzle will the bullet be 1.0 s after it is fired? Homework Equations The Attempt at a Solution I know that i have the time (1 s) and the velocity (655...

Me and a few friends of mine were discussing if mass plays a role in the speed of a free falling body. They argued that equal bodies (same volume, same geometry) with different weights (mass) would fall at different velocities. I defended that mass has no part on the matter, but only air...

Homework Statement A ring falls through a horseshoe magnet. Before reaching the magnet, is the current induced in the ring clockwise or counterclockwise? What about after the ring has passed through the magnet? The answers are clockwise before the ring passes through, and...

I was trying to do this problem, but I got t negative, so I went back from the beginning and looked for my errors, but I couldn't find one. Can anyone tell me what I did wrong ? Thanks You drop a ball from a window on an upper floor of a building and it is caught by a friend on the ground when...

Homework Statement A ball is thrown straight up. If its initial velocity is 24m/s, how high does it rise before it begins falling down? Homework Equations The Attempt at a Solution This one is very frustrating to me. My teacher doesn't teach us, he just gives us the homework and...

Let's say that body with rest mass m0 is falling toward gravitating body from infinity. Near gravitating body it falls with speed v=\sqrt{\frac{2MG}{r}} Is it right that relativistic mass of body falling at speed v near gravitating body is equal to the rest mass of the same body at infinite...

It is well know that it takes pi*m time to go from rest at the surface of a Schwarzschild black to the singularity. How much time does an external observer at infinity experience then in that time? How do I show it?

Homework Statement I basically need to find the resulting motion of an object that is falling through the Earth. I also need to find how long it takes. I am ignoring friction and assuming the density of the Earth is constant. 2. The attempt at a solution Here is an image of my work. (I...

A ball, dropped from rest, covers three-quarters of the distance to the ground in the last second of its fall. a) From what height was the ball dropped? b) What was the total time of the fall? Hey, I don't know how to approach these types of problems. Help?

Simple question, if the force of gravity is proportional to mass and distance, as in Newton's and Einstein's theories of gravitation, then why do people say that objects with two different masses accelerate at the same rate independent of mass on earth? Can Galileo's rule just be a practical...

Homework Statement A student stands at the edge of a vertical cliff and throws a stone vertically upwards. The stone leaves the student's hand with a speed of v=8.0m/s, the acceleration of free fall is 10m/s2 and all distance measurements are taken from the point where the stone leaves the...

Spiderman steps from the top of a tall building. He falls freely from rest to the ground a distance of h he falls a distance of h/4 in the last 1.0 s of his fall. What is the height h of the building? The attempt at a solution is on the photo. I am stuck and don't know where to go...

Homework Statement A person trips against a table, causing a glass to fall off the edge. An excellent human reaction time is 0.25 seconds. In that time, how far wil the glass fall? Assume that immediately (after 0.25 s has elapsed) begin to acclerate your hand so that you grab the glass when...

Homework Statement A 45 kg woman jumps from a height of 2.5 meters to a solid floor. In an attempt to minimize the likelihood of injury, she lands on the ball of her feet (the pads just behind her toes) with her knees bent. What average force is needed on her feet to stop her fall if her...

Homework Statement For my physics practical I have to conduct an experiment where I have to investigate the acceleration of a small cart, its a block of wood with wheels on it. The set up is I have a one metre distance marked on a desk from the edge of the desk. at the edge of the desk...

Homework Statement "What force keeps the electron from falling into the nucleus of the atom?"Homework Equations The Attempt at a Solution I have three hypotheses: 1. Neutrons have a negative charge (although there is not only electron capture but also b+ decay) 2. The electrons in the...

Hi all, I'm considering a problem of a bunch of particles (say electrons) arriving on a plate. If the plate is orthogonal to the direction of motion of the particles their distribution (on the plate) is a gaussian distribution centered in a point (x,y) of the plate with standard deviation...

Homework Statement A small mailbag is released from a helicopter that is descending steadily at 2.68 m/s. (a) After 4.00 s, what is the speed of the mailbag? v = ? Homework Equations The Attempt at a Solution

Homework Statement Nicole throws a ball straight up. Chad watches the ball from a window 6.10 m above the point where Nicole released it. The ball passes Chad on the way up, and it has a speed of 11.0 m/s as it passes him on the way back down. How fast did Nicole throw the ball? Homework...

Homework Statement For small, slowly falling objects, the assumption made in equation (1) (see below) is good. For larger, more rapidly falling objects, it is more accurate to assume that the magnitude of the drag force is proportional to the square of the velocity with the force...

Homework Statement A 7500-kg rocket blasts off vertically from the launch pad with a constant upward acceleration of 2.25 m/s^2 and feels no appreciable air resistance. When it has reached a height of 525 m, its engines suddenly fail so that the only force acting on it is now gravity. (a)...

Homework Statement Hi, this is supposed to be an easy question, but for some reason I can't get it to work. The question is: A weightless rod is hinged at O so that it can rotate without friction in a vertical plane. A mass m is attached to the end of the rod A, which is balanced...

Homework Statement A shipyard worker drops a hot steel rivet (mass 125g, temperature 350 degrees C) into a river at temperature 5 degrees C, a distance 30m below. Stating any assumptions you make, calculate the entropy change of the universe as a result of this event. (specific heat capacity...

First, let me preface this question that I have been out of academia for about 5 years now, and am just starting to get back into it, although it seems my Calc/Kinematics is a little rusty.b]1. Homework Statement [/b] An object of weight W is falling through a medium such that the object's drag...

Homework Statement A plank of lengt 2l leans against a wall. It starts to slip downward without friction. Show that the top of the plank loses contact with the wall when it is at two-thirds of its initial height. Hint: Only a single variable is needed to describe the system. Note the motion...

In lecture 2 of his series on Classical Physics, Prof. Balakrishnan asks how many degrees of freedom there are in a system consisting of a falling piece of chalk. Looking at my notes, I'm not sure I understand the concept. Is the answer 6 (3 of position, 3 of orientation), or 12 (3 of position...

Suppose I drop a rock off a cliff at height h. As it falls, I snap a million photographs at random intervals. On each picture I measure the distance the rock has fallen. Ignoring air resistance: x(t) = 1/2 g t^2 v(t) = g t total flight time = T = Sqrt[ 2 h/g] My confusion is that in...

Homework Statement A 15 kg bucket of water is suspended by a rope wrapped around a windlass, that is a solid cylinder .3 m in diameter with mass 12 kg. The cylinder pivots on a frictionless axle through its center. The bucket is released from rest at the top of the well and falls 10 m to the...

Homework Statement A ball with initial velocity 0 and mass m starts at the top of a hemisphere and begins to slid down the frictionless side. The radius of the hemisphere is r. At what angle does the ball fall off the hemisphere?Homework Equations mgsintheta, mgcostheta, fn mv^2/rThe Attempt at...

Homework Statement (Irodov - Problems in General Physics - 1-31) A ball starts falling with zero initial velocity on a smooth inclined plane forming an angle α with the horizontal. Having fallen the distance h, the ball rebounds elastically off the inclined plane. At what distance from the...

The light should accelerate towards the earth, the same way as massive objects are attracted towards the earth[General relativity]. We may not find path of the light to be curved because of the enormous velocity of light, the curvature of light is too subtle for our senses. Consider a...

Hello Forum How much falling water would I need to potentially generate 3 KWatts (240 ACV @ 13 A) of electrical energy? Assume we have 100% efficient electrical turbine generator. Our location is residential so the height drop is restricted to say 5 meters max, the lower the better...

I apologize many times in advance for asking what I suspect to be that which is the most repeated question on this site. Last night over dinner with friends, somebody whose judgment was impaired dared me to prove that two falling objects released simultaneously (the usual suspects like friction...

I don't know if this is the right place to post this but would a proton falling into a black hole experience tidal forces. If the proton is like a wave could we stretch the wave out, that is probably really bad wording. Or does the quantum of energy move all together?

Say I stick half of my body through the event horizon of a super massive black hole. I say a super massive black hole because in this case the event horizon radius will be very large and the tidal forces will not be as strong. Why can't I pull myself out if the force on the part of my body past...

[SIZE="4"]"danR This nicely puts what has been a problem for me: we've imbedded motion in a static 4-space geometry. Why should particles 'simply start following' the geodesics...? What does 'following' mean? Is it simply a description of the necessary direction of entropy? But isn't entropy...

First of all, hi! I'm new here. Homework Statement Rather than a specific problem, my friend and I are doing an Extended Experimental Investigation on the energy transfer of dominoes for our grade 12 assignment. 2. The attempt at a solution We have approached it using loss of gravitational...

Homework Statement A particle falls in Earth's gravity. The force of air resistance is F = −αv v where v is the velocity, v is the speed, and α is a constant. (The direction of the force is opposite to the velocity, and the magnitude of the force is αv^2.) If the terminal speed is 20.2 m/s...

Homework Statement A flexible chain of mass M and length L lies on a frictionless table, with a very short portion of its length L0 hanging through a hole. Initially the chain is at rest. Find a general equation for y(t), the length of chain through the hole, as a function of time. (Hint...