Falling Definition and 1000 Threads

Homework Statement the question is about a very flexible strain falling on a rigid table and ask for expression of normal reaction of table at a certain instant Homework Equations when i was trying to solve problem , i resolve N(normal reaction) into N1, N2 which N2 is the weight of...

Hi, If a baby learning how to walk loses balance and falls sideways from an upright position (whilst standing), how long before the baby hits the ground, i.e how much time does one have to catch the baby? Is the time in that case still equal to SQRT(2*baby's height/9.81)?

Homework Statement A ball is thrown vertically upward with an initial speed of 20 m/s. Two seconds later, a stone is thrown vertically (from the same initial height as the ball) with an initial speed of 24 m/s. At what height above the release point will the ball and stone pass each other...

So I've studied physics at the university quite a bit and was a bit surprised when I couldn't answer this simple question a friend asked me. When something lands in water why are several ripples created? Like why is the resulting water wave made up of several peaks and valleys and not just one...

How to derive a formula for speed of falling body in Earth atmosphere? I know distance from surface, pressure at this distance, object mass, falling start point and point where I want to calculate the speed.

Homework Statement The 37lbs(16.78kg) baby falls from a 50feet(15.2m) building, The baby's Δx on the mans arms is 1m. I already got his velocity and acceleration during the 1m he is on the mans arms. a(during the time the baby is on his arms)=150m/s/s v(inicial)=17.3m/s I said...

Homework Statement Two rocks are falling from a roof. The second one begins its fall when the first one has already covered 30cm. Calculate the distance d between these two rocks after 10 seconds counted from the moment the second rock begins its fall. Homework Equations...

Homework Statement A meteor has a speed of 94.0 m/s when 700 km above the Earth. It is falling vertically (ignore air resistance) and strikes a bed of sand in which it is brought to rest in 3.03 m. a) What is its speed just before striking the sand? b) How much work does the sand do to...

Hi! This isn't exactly a homework question - I am not studying physics (though I was good at high school physics once-upon-a-time) it is just something that I am interested in and Google isn't being very cooperative. If this is in the wrong place, please let me know - I thought since it is such...

Homework Statement I just had an exam in physics and there was this one easy question that I just couldn't wrap my head around. A skydiver (85kg) is accelerating at 3m/s^2. What is the force of the air resistance on him? Homework Equations f=ma and other mechanics The Attempt at...

The exact problem reads: The acceleration of gravity g is a constant only for a limited range of height differences. A better approximation, one that might hold over a larger range of height differences, is that g decreases linearly with height, g = go - hg', where h is the height measured from...

Hi Guys, I have been asked to find out at what point a measurement device go out of calibration when dropped and express that in a g as in G force. Its been 15 years since I studied physics (for 3 years), I do rememeber a bit but I need some help.. I have the size and weight (mass) of...

Homework Statement A rock with a weight of 120 N free falls from height of 2.00m collides with with Earth and digs 60 mm into it. What is the Earth's average force of resistanceHomework Equations F=m*g => m=F/g m*g*h = 1/2*m*v^2 v=√(2*g*h) The Attempt at a Solution I found the...

Homework Statement A falling object moves so that its height x above the ground at time t is given by the following equation: x = 100 m - (4.9 s-2)t2. Find its average velocity from t = 0 t t = 2 s. Homework Equations Average velocity = Δx/Δt The Attempt at a Solution I was...

Homework Statement In a physics exam I have this question: "what is the momentum of the weight force of an object in a free fall relative to its center of mass?" Homework Equations Is my answer right ? The Attempt at a Solution My answer is: "If we try to calculate the momentum...

Homework Statement A particle is release from rest (y=0) and falls under the influence of gravity and air resistance. Find the relationship between v and the distance of falling y when the air resistance is equal to (a) αv and (b) βv² The Attempt at a Solution Setting the origin at the...

Homework Statement 1. You stand on a spring-loaded bathroom scale in a bathroom. The scale "reads" your mass. What is the scale actually measuring? 2. Similarly, you stand on a spring-loaded bathroom scale in an elevator that is accelerating upward at 2.0 m/s^2. The scale "reads" your mass...

Homework Statement A certain freely falling object, released from rest, requires 1.65 s to travel the last 39.0 m before it hits the ground. (a) Find the velocity of the object when it is 39.0 m above the ground. (Indicate the direction with the sign of your answer. Let the positive direction...

Homework Statement How does the study of free falling objects on Earth inform us on the motion or lack thereof of the earth? Homework Equations The Attempt at a Solution

There is a drop of mercury in an elevator (flat on the ground). during freefall what will happen to the mercury.

I was recently thinking about potential energy and I came to two conclusions which contradict each other- 1)When a body is falling from a height, the force of gravity is acting on it in the downwards direction. There is displacement in the downwards direction. So as the force and the...

A uniform chain of mass M and length L is held in vertically in such a way that its lower end just touches the floor. The chain is released from rest in this position. Any portion that strikes the floor comes to rest. Assuming that the chain does not form a heap on the floor, calculate the force...

Homework Statement A ball of mass 0.163 kg is dropped from a height 1.89 m above the ground. The acceleration of gravity is 9.8 m/s^2 Neglecting air resistance, determine the speed of the ball when it is at a height 0.997 m above the ground. Answer in units of m/s Homework Equations...

Let's say I start out a few thousand kilometers from a black hole, and I begin to move toward the black hole due to it's gravitational pull. What type of time dilation would I experience as I fell into the black hole before the event horizon, and after the event horizon? By the time I die...

QUESTION: Say you have two spools of thread. Let's assume it's a sturdy, but mass-less thread. You unwrap one spool entirely and gather up the loose thread in your hand in such a way that it doesn't knot, and let it hang from a certain measured height. The other spool you hold from the same...

I take it that it would be ok that in the classic demonstration of Lenz's law with the falling magnet, to replace the magnet with some quantum particle of non-zero magnetic moment and make the tubing a solenoid in order to generate a current as the particle fell? Obviously the current would be...

Homework Statement An object is falling from rest with air resistance modeled by $$kv_x$$. Where v_x is the object's velocity in the x-direction (downwards). Find an expression for the speed of the object as a function of time. Homework Equations $$mg-kv_x=m\frac{dv_x}{dt}$$ The...

What is the formula of the velocity and time taken of an object faling in water? I have the mass, the density, the volume of the object and the height distance of the falling object. I know that the drag force is included in the formula but i have idea how to calculate it. So anyone knows this?

Homework Statement I have a magnetic ball with magnetization M, mass m and radius R that starts to fall from rest through conducting tube of radius a little big larger than R, thickness \Delta and conductivity \sigma. The ball is not rotating, it said that magnetization is oriented vertically...

In GR a object follows a geodesic when free falling as I understand. A object near the sun for instance wil fall to the sun following that line. If the initial speed is different the path will be different. How can it be that the geadesic is depending on the initial speed of the object...

Homework Statement I have that system and the problem says: A disk of mass M and radious R are posed are shown. The disk is hanging by an ideal rope which is coiled up. From a smooth axis through the center of the disk is haning a body m. Calclate the module of the aceleration of the...

So a sadistic friend of mine posed this question: Of course this question can be thought of in two ways: a) would the surface still be hot enough at the bottom or b) would the interior be hot enough at the bottom (since the coals would probably break, its a relevant question). At the time...

Let an object of mass 'm' and volume 'v' be dropped in water from height 'h', and 'a' be the amplitude of the wave generated. What is the relation between 'a' and 'h'. How many waves are generated? What is the relation between relation between the amplitudes of successive waves?? Assume the...

1: Does an observer, standing on the moon, see a brick, that is falling straight down, to contract? 2: Does an observer, standing on the moon, see a light pulse, that is falling straight down, to contract?

Ok, first time posting...hopefully I do this correctly, as I have found myself in a bind on this one. It is a question comparing the mechanical energy of two masses falling in different ways in which you are given the option of greater than, less than, or equal to. Homework Statement The...

Why is there no redshift in a freely falling frame? The photon in a freely falling frame also rises in the gravitational field, so isn't it supposed to be redshifted?

Homework Statement Someone is free falling off a cliff. 20 m below the clifftop they scream with a frequency f. a) What does a person standing at the top of the cliff hear? b) what will they hear when the person is 40 m below the cliff? Homework Equations f'=f(v+-v_d)/(v-+v_s) The...

Homework Statement Hi, I'm trying to determine g (very precisely) using a falling ball in non-vacuum. I'm using three laser beams (along the z-axis), they're detecting when the ball enters the beam and leaves it again. This will give me six different times. To only problem is that we don't know...

If an object falls there are two ways to consider momentum conservation Way 1: The system involves just the object therefore the gravitational force is an EXTERNAL force so momentum is NOT conserved Way 2: The system involves object and earth. The increase in momentum of the object down...

Hi. Wikipedia says, that for the external observer, time stops at the event horizon. Is then, for the external observer, anything falling below the event horizon? Or rather, every piece of matter stops before the horizon?

I explained to myself that I don't fall through the ground due to electrons repelling. Using classical electrostatic repulsion. Once in a while I hear it explained through Pauli's exclusion principle (PEP). Do we need PEP to explain this, or is classical electrostatics enough?

Homework Statement find relationship between the angle and time of a tilted falling object Homework Equations any that is applicable The Attempt at a Solution As seen in picture below, and that's what I have done so far. It's a tilted object, only gavity and the support...

I live in an apartment, and today I heard what seemed small rocks falling in one of the walls (it's a wall that goes through the center of the building), several times. Is this normal?

Homework Statement hi I'm trying to design a small experiment based on soil pressure i've not had much use of some of the equations and principles for a few years so I'm a little rusty basicly I'm trying to exert pressures onto grass seeds (lolium perenne) in a rough field experiment in...

A falling object with no initial velocity with mass m is influenced by a gravitational force g and the air resistance which is proportional to the object´s speed. By Newton´s laws this can be written as: (1) mg-kv=ma or (2) mg-kv^2=ma (for large velocities). I assume that k is a...

Homework Statement Suppose that there is a negligibly thin tree in the forest of infinite length that begun tipping over. Negating frictional effects from the pivoting, does the tree ever hit the ground? Homework Equations My approach was to solve the problem for a tree of length l and...

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}{...