Falling Definition and 1000 Threads

Homework Statement String is wrapped around two identical disks of mass m and radius R. One disk is fixed to the ceiling but is free to rotate. The other is free to fall, unwinding the string as it falls. Find the acceleration of the falling disk by finding the lagrangian and lagrange's...

Hello everyone, I have a homework question for general relativity that is driving me nuts. It goes like this: An observer falls from rest at radius 10GM in the spacetime of a black-hole of mass M (in natural units). What time does it take for them to travel from a radius of 6GM to 4GM...

Hi all, So I'm having hard time going through my physics courses. I tend to fall behind in the middle of the semster and once I'm behind it's hard to get myself on track again. So I am taking Classical Mechanics using Taylor's textbook. And Quantum Mechanics using griffiths I want to...

Having discussed recently https://www.physicsforums.com/threads/rod-falling-radially-towards-the-center-of-a-mass.871169/ I'm now puzzled by the question, what happens to the rod during his radial fall through the event horizon and what would the hypothetical observer at ##r=2M## measure...

Homework Statement Stretchable ropes are used to safely arrest the fall of rock climbers. Suppose one end of a rope with unstretched length ##l## is anchored to a cliff and a climber of mass m is attached to the other end. Ehrm the climber is a height ##l## above the anchor point, he slips and...

Homework Statement Consider a rod of length ##L## that is attached to a hinge making an angle ##\theta## with the horizontal. There is a force ##\vec{F}## acting vertically on the rod that creates constant angular velocity ##-\omega##. If there is fluid under the rod with constant density...

Homework Statement This is a question regarding Problem 7.11 in Griffiths Electromagnetism book, which considers a falling square loop of aluminum through a uniform magnetic field pointing into the page with only part of the loop in the field at t=0 (see picture below). To solve this...

Homework Statement A straight rope is dropped at a height where is it not touching the ground. The rope has 10 beads spaced out on it and tied so they do not move. From the bottom to the top, the space between the beads increase, where the distance is the smallest at the bottom and largest at...

Homework Statement A falling stone takes 0.28 s to travel past a window 2.2 m tall. From what height above the top of the window did the stone fall? So from this problem I think I have these variables: vo = ? (or 0 because falling usually indicates 0 for an initial velocity?) yo = 0 y = 2.2m...

1. problem: a body of mass started to fall from rest, and from S elevation. what is the equation that calculate the force of what this body will hit the ground? Homework Equations :[/B] F=mg // which is used to calculate the force of the body on the ground when it is already on the ground...

Homework Statement In this problem you will do numerical computer calculations. A skydiver of mass 75.0 kg jumps out of a plane at an altitude of 30.0 km above the surface of the Earth. His parachute fails to open. Assume there is no horizontal motion and the initial velocity is zero. We...

Homework Statement Consider a particle in a gravitational field that is also subject to a resisting force proportional to the velocity squared ( Fdrag = + or - cv2). a) Find the terminal velocity, vT, for the object as it falls. b) Show that for an object dropped from rest that the velocity...

I searched engineering calculators and they rely on the input you know the stopping time or the stopping distance - easy for a car but not an egg. Knowing either of these quantities makes the problem trivial, but how to estimate or calculate them?? What is the best assumption for either and...

Homework Statement 4 m masses, μ is the coefficient of friction. what is the tension and what should the maximum μ be to allow acceleration. Homework Equations Mass-acceleration: F=ma The Attempt at a Solution $$\left\{\begin{array}{l} mg-T=ma \\ T-3mg\mu=3ma...

Will liquid metals create droplets when falling or will they create different shapes?

Homework Statement While standing at the edge of the roof of a building, you throw a stone upward with an initial speed of 6.91 m/s. The stone subsequently falls to the ground, which is 16.5 m below the point where the stone leaves your hand. At what speed does the stone impact the ground? How...

Hello, I've got a problem and I have no idea how to start. I'll be happy for any hint. Thanks Homework Statement Two beads each of mass m are at the top (Z) of a frictionless hoop of mass M and radius R which lies in the vertical plane. The hoop is supported by a frictionless vertical support...

Homework Statement Let's have a disk and massless rope tangled in it. One end of rope is tied to the ceiling and the disk is falling freely down. System has one degree of freedom. As a coordinate we can choose angle ##\phi## which says an angle of rotation from the start position. Find from the...

Homework Statement A rock is thrown straight upward from the edge of a 30m cliff, rising 10m, then falling all the way down the base of the cliff.Homework EquationsThe Attempt at a Solution Well, because the rock was thrown 10m up, and then it came all the way down, I added those quantities...

It boggles my mind how a car's subframe is only held on by a few bolts and some rubber bushings. How is it that the bolts don't just shear off? It would seem that the forces of driving, sometimes erratic, should easily overcome the strength of a bit of metal. People have been putting in...

Hello, new member here so first post, I apologize for any unintentional faux pas. Anyway... I have a problem which I have been asked to sort out in my work place. We have a rig which is used to move a pneumatic ram up and down. Currently it is on an electrical winch system and I have been...

Homework Statement An object falls under gravity and air resistance force bv. It is known there is a characteristic time τ=m/b such that the object comes close to the terminal velocity for t>>τ. Derive an exact expression for the distance d traveled at time t. Homework Equations not sure...

Consider an ensemble of identically prepared pencils balanced on its tip. If a pencil is precisely vertical, ##x=0##, and precisely at rest, ##p=0##, then it will never fall. But some pencils in the ensemble would fall, because according to the uncertainty principle, the standard deviation...

The time taken for a free-falling object to fall a set distance (on earth) is, according to Wikipedia, described by the equation: t = √(2d/g). Why is the distance doubled in this equation/ how is this derived?

Conceptual question that's seemingly abstract: There is a barrel of water that is bottomless, or has an infinite amount of water in it. It is upside down and thus releasing water from rest at Earth's acceleration. The barrel is suspended in the air and there is an onlooker on the ground...

Does anyone have any stories of close calls from objects falling out of windows of high rises in the city (or elsewhere)? I was watching the Ken Burnes series on the civil war recently and they said that the women in New Orleans used to dump their chamberpots on the occupying Union soldiers...

Ok so what I want to create is a simulation of how the acceleration of a person falling would change according to the person's mass and height. This would then be explored in Matlab. Therefore, first, I am trying to find out the equations that would relate acceleration motion with mass and...

This example might be not very interesting, but perhaps helps to improve my understanding. Is a radially falling rod in free fall? Which frequency shift of light emitted at the ends of the rod would observers at rest at the respective other ends measure? Here are some assumptions. Please...

Homework Statement I am trying to prove a human head hitting the ground after falling backwards down a hill suffers a significantly greater impact than one hitting the ground on a flat surface. The person is 95KG, 180cm tall, and the impact point of the head was 60cm below (in altitude) the...

Homework Statement A cylinder of mass M and radius r is at distance l0 from the edge. mass m is hanging from a rope. no friction at the weightless pulley. the cylinder starts rotating without sliding. What's the acceleration of the COM of the cylinder. What's the velocity of the COM of the...

Warren falls over his tackle box and lands in a canoe 0.95 m below the side of the dock. Warren's mass is 70 kg and the canoe has a mass of 72 kg. Warren and the canoe move 1.73 m away from the dock in 1.005 seconds. relating equations are Vi = Vf - at v = d/t A = change in velocity/time...

Homework Statement A person looking out of a window of a tall building sees a bucket fly past the window at 30 m/s, then hears the bucket hit the ground 8 seconds later. At what altitude is the observer located? Assume negligible air resistance and speed of sound at 340 m/s. The problem I am...

Homework Statement Suppose a rain drop with mass ##m_0\neq 0## is falling due to gravity with initial velocity ##v_0##, assume ##\frac{dm}{dt}=k=##constant. Solve the differential equation and determine the velocity as ##t\to\infty## Homework Equations ##F=\frac{dp}{dt}=\dot{m}v+m\dot{v}## The...

Centrifugal force due to rotation of the Earth has among its effects the deviation towards the equator of a ball falling from height ##h## vertically on Earth. I do not understand what is the inertial explanation of this phenomenon. Once the ball is released there is no centripetal force that...

I don't understand what are the causes of the Coriolis effect for objects moving with respect to Earth. For istance consider an object free falling on the Earth from an height h. Its tangential velocity its greater than the velocity of an object on the surface of Earth, hence it moves eastward...

In the book I'm reading, there is a discussion about how a person inside a "box" falling in a gravitation field would see himself as compared to someone on the ground. It is as follows "While the guy is asleep, put him in a spacious box elaborately furnished inside to look exactly like his...

I was wondering what is known about the speed of objects falling to the centre of a Black Hole? If a number of identical objects, initially located outside the event horizon, were propelled at varying speeds towards a black hole, would that variability be maintained as they pass through the...

Take an object of negligible mass that is dropped from rest 2 kilometers away from a neutron star of mass 1.989*10^30 kilograms (1 solar mass) and radius 7,802 meters. How long will it take the object to reach the surface of the neutron star? I'm not terrible at calculus, but I know for a fact...

According to (4.93), it should be eastwards. But intuitively, shouldn't it be westwards since the Earth is rotating from west to east?

Homework Statement I am doing a project on pressure sensitive films and finding if they indicate the correct amount of impact. I have carried out an impact test by dropping a mass of 5KG from a height of 1m. I have calculated the velocity to be 4.43m/s. The kinetic energy just before impact is...

Homework Statement Solve the differential equation, dt/dv= 1/g (1/1-a^2*v^2) where a = (k/mg)^1/2 to yield v= 1/a(1-e^-2agt/1+e^-2agt). Homework Equations F=ma Newton's 2nd Law Integration Laws The Attempt at a Solution See image. I think I'm getting messed up on the integration laws.

Homework Statement Homework Equations How to locate the point P and C after 0.5s from their initial position ? The Attempt at a Solution Well i don't know whether it would be correct way to start the problem i.e find the centripetal acceleration .

Homework Statement A plane mirror of length 20 cm is put up in a wall.The upper part of the mirror is 130 cm above the ground.A person is standing 1 m in front of the mirror.The person's eye is 130 cm from the ground.Suddenly,the mirror falls.How long is the person able to see the tip of his...

Homework Statement This is a Lab: A Ball is placed on a 14cm high ramp and it rolls down to the bottom of the ramp and onto a table where it rolls 20cm (the ramp's horizontal displacement is 16.5cm). After rolling on the table, the ball falls off the table for 76.5cm with a forward horizontal...

Homework Statement A rope with uniform density ##\lambda=\frac{m}{L}## is placed on a frictionless table with an initial length ##y_0## hanging through the hole. Derive a differential equation for the position of the bottom of the rope and then using this solve for the time required for the...

Homework Statement This is an academic project related to a falling object simulation. I have come to the point where I'm trying to calculate the per degree angle of the falling object seen in the attached images. The object has known height and length in pixels and is fixed on a pivot...

Hi, I'm preparing a computer software to simulate the fall of an object for an academic project. The object is rotating (not rolling) over the circular bottom point. I know that the angular velocity at the horizontal point is ω = √(3g/L). I would like to calculate the angular velocity at every...

in science shows , an airplane made to fall freely under gravity has its passenger floating in mid air i understand weightlessness is due to 0 normal reaction by floor on person but since both passenger and plane have same aceleration due to gravity what might be reason for relative separation...

Homework Statement The speed of a falling body might be based on the observation that the velocity of a falling object seems to increase the further it has fallen. Model the hypothesis "The speed of a falling object is proportional to the distance it has fallen" as a differential equation...

Homework Statement The free fall acceleration of a mass ##m## above the Earth's surface in one dimension can be represented by ##m\ddot{y}=-\frac{mMG}{y^2}## where ##M## is the mass of the Earth and ##G## is the gravitational constant. With ##\dot{y}(t=0)=0## and ##y(t=0)=y_0##.. (1) Find an...