Questions tagged [free-fall]

Free fall is any motion of a body where gravity is the only force acting upon it. In general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it.

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Is the acceleration of a falling object constant? Explain [duplicate]

My name is kakari john I come from wiawso
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What would happen if when falling down you get pushed up?

I know it will be a weird question, but im not a physics well informed person and I had this unsolved question for long time. What would happen if lets say you are falling with someone else from ...
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Electromagnetism as curvature of space-time? [duplicate]

If gravity can be expressed as a curvature of spacetime, can electromagnetism similarly be expressed as curvature on higher dimensions of spacetime? Also (I'm not sure if the 2 questions are linked), ...
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Free Fall with non-constant acceleration due to gravity [duplicate]

In a free fall motion, the height of the falling object is constantly changing and its acceleration due to gravity is also changing. However, we usually ignore the effects of changes in height on the ...
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Gravitational collision [duplicate]

Two point particles of exactly the same m = mass 1kg is separated by a distance of d = 4m. After how much time, they will collide with each other due to the force of gravity? Assume that, the ...
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Is there a bug in this step (and how to fix it?)

Reading an old book of classical mechanics (Spiegel's theoretical mechanics) I came across a passage that I would like to clarify. In order to find the equations of motion of free falling point ...
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Free Fall time in General Relativity

Suppose you are working with the Schwarzschild metric in GR. $$ -c^2 \mathrm d \tau ^2 = -c^2 \left (1 - \frac{2 G M}{c^2 r} \right) \mathrm d t^2 + \left (1 - \frac{2 G M}{c^2 r} \right)^{-1} \...
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How can we conduct experiments to verify formulas without special equipment? How was it done in the past?

If we wanted to verify experimentally/empirically as laymen without special instruments a formula such as $s=16t^2$ which is used to approximate the distance s, in feet, that an object falls freely ...
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Calculating the total time of the movement in horizontal movement

"On the top of a 30m building there is a ball. At some moment, a force started to act on the ball which gave it an acceleration on the roof of $0.5[m/s^2]$ for 15m. since the moment that there ...
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Differential equation of the free falling object with air resistance

I'm puzzled by the result I get when I try to solve the differential equation for an object that is falling subject to air resistance. Suppose the $y$-axis is directed upwards, then $\vec{F_a}=bv \hat{...
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A ball is dropped from a height of 1m above the ground.What will be the instantaneous speed of the ball when it is exactly at 1/2 mark? [closed]

I saw this question in this video Instantaneous speed (differentiation) by Don't Memorize In the video, the instantaneous speed of the ball is given as 100cm/sec which is equal to 1m/sec but when I ...
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Height of a table: what's the uncertainty?

I would like to introduce high school students to error analysis with a simple experiment: find $g\pm \Delta g$ by measuring the time a ball takes to fall from a table, repeating many times. ...
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Doubts about work-energy theorem and negative gravitational potential energy

A ball is dropped from a certain height. The work done on the ball by the gravitational force is $$W = F \cdot h = mgh$$ and the gravitational potential energy is $$U = -mg h$$ The difference in ...
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Is there a difference in energy required to make 2 items with the same exact mass but different material travel the same distance whilst in free fall?

is there a difference in energy required to make 2 items with the same exact mass but different material travel the same distance whilst in free fall? Please answer for all cases of free fall: ...
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Why acceleration due to gravity same for two objects of different masses (neglecting air resistance)? [duplicate]

If a feather ball and bowling ball are thrown , both reach the ground at the same time. (neglecting air resistance) The reason given to this is that Both the bodies have same acceleration . My ...
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In general relativity what is the relative velocity between a fixed observer and one free-falling from a finite radius?

This question is the last missing link for me to solve my other question here. In general relativity, what is the relative velocity between an observer in free fall from a distance $r_1$ from a mass $...
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Falling to Earth from Orbit [closed]

Suppose we ascend to a height $h$ away from the surface of the earth and drop an object. High school physics tells us that it will accelerate at a speed of $9.8 \frac ms$ and will hit the ground in $\...
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How deep would a hole need to be before you could no longer hear the sound of a small object hitting the bottom?

Assuming there are no obstructions, background noises, and the bottom of the pit is just flat concrete, if the average person were to drop something like a padlock (very specific, I know) into the ...
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Rotation of a freely falling body

Suppose a straight rod with one end denser than the other is dropped from a height at an angle. Will the rod hit the ground at the same angle or will air resistance cause it to straighten and hit the ...
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1 answer
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Michelson-Morley interferometer in free fall

We suppose that we have a Michelson-Morley interferometer in free fall, will there be no interference: the round trip time in both arms of the interferometer is the same?
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3 answers
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How does a virus fall down in static air?

If we drop a virus from a height, in static air, will it fall to the ground like a lead ball, a balloon, or like a virus? How will it fall to the bottom? Like a Brownian particle? It will not float ...
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2 answers
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What would reach the ground first? [closed]

Hi I’m trying to get my head round this if a bowling ball and coin from the Empire State at exactly the same time what would hit the ground first I know that gravity = 9.81ms-2 but what else am I ...
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Initial speed of a released object from a moving object

For example, if a helicopter is moving upwards in constant velocity of 20 m/s and at some height an object is released from the helicopter, why does the object has an initial velocity of 20 m/s and ...
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Confusion Regarding Reaction Forces and Newton's Third Law of Motion [closed]

So I was confused about reaction forces for a LONG TIME and I have finally been able to clear some of my confusions, but the concept is still not totally clear to me. Can someone confirm whether my ...
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Free fall with sound [closed]

One of my colleagues affirm that the following problem is not solvable while I think it is. Consider a body falling from rest inside a pit/well of unknown's depth ($h$). Taking into account that the ...
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What shape the Earth would have to be for an object in free fall to follow a straight line trajectory?

I was explaining to my 8 year old daughter that objects in free fall follow an elliptical trajectory instead of the commonly believed parabolic one (source: https://www.forbes.com/sites/...
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What happens to charges when a uniform wire is accelerating due to earth's gravitational acceleration?

Let me say this in a simple way. I was just curious to know whether charges experience a pseudo accelerational force in a wire when in freefall. The charges are supposed to feel a pseudo force right? ...
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Why is wingsuit water landing without opening a parachute not a survivable event?

According to this YT video, just before this wingsuit flyer opened his parachute his speed was below 90 KPH. When you jump off a 100 foot cliff your impact velocity is around 87 KPH and people have ...
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Im confused on why did my prof. put height as -14m on this question. can someone explain? [closed]

The question is A snowball rolls off a barn roof that slopes downward at an angle of $40^\circ$ The edge of the roof is 14.0 m above the ground, and the snowball has a speed of $7.00\ \mathrm{ m/s}$ ...
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What numbers would I apply to the equation $y=y_o+v_ot+\frac 12at^2$ using this simulator?

Using a Projectile Motion Simulutator (selecting INTRO from the four choices), I set the height of the Cannon at $15 \ \text{m}$, Initial Speed = $8 \ \text{m/s}$, the bulls-eye at $13.9 \ \text{m}$. ...
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Time to hit ground after dropping object [closed]

I have an object that is 9 meters above the surface of the earth, in vacuum. If I drop it I'm trying to figure out how long it will take to reach the ground. My teacher gave me the formula below, I'...
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Height vs Pressure of a ball (using audio method)

I am doing an experiment for my IA which is me holding a basketball from one meter and letting it bounce at different pressures. For measuring this I am going to use a method that I have read about. ...
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1 answer
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Stone falls from a balloon thats descending @ 12 m/s. What will be the displacement of the stone from the point of release after 10 seconds? [closed]

Question based on Motion in a Straight Line: “A stone falls from a balloon that is descending at a uniform rate of 12 m per second. What will be the displacement of the stone from the point of ...
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1 vote
2 answers
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Distance and velocity increased by $g$ units every second

Distance fallen in every second gets increased by $g$ units. Velocity is increased by $g$ units every second. Is it true that distance and velocity increases by $g$ after every second? If it starts ...
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Why is the rate of change of velocity with distance not constant?

My physics textbook says, "Galileo concluded that the rate of change of velocity with time is a constant of motion for all objects in free fall. On the other hand, the change in velocity with ...
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19 votes
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Does a long vertical pole fall at a different speed than a short vertical pole?

The formula for a falling object has $r^2$ in the denominator. This would mean that an object that is higher up falls more slowly than the standard $9.807\ \mathrm{m/s^2}$ that we are taught in high ...
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How do time elapse for free falling clocks vs. clocks in flat space-time? [duplicate]

Complete re-edit. Trying to rephrase my question, based on some good comments. Made several questions in the hopes that they combined paint the picture and that atleast one of them is understood :) Q1:...
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3 answers
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Does this proof of "all bodies fall with the same acceleration" presuppose the identity of gravitational mass and of inertial mass?

It seems to me that one way to show that all material objects have the same acceleration in the gravitational field of the Earth (independently of their mass) one can make use of these two formulas. I ...
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2 answers
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Who moves when an object falls by gravity? [duplicate]

I'm reading calculus book by Morris Kline. This book treats physics because calculus grew out of physical and geometrical problems. I have no background about physics and got a question while reading ...
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Freefall time of human body with/without air resistance

I am trying to calculate how long does it take for a human body ($100 \;\text{kg}$) to fall from $120 \;\text{m}$ with what end speed. (With air and in vacuum). I googled something about drag ...
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1 answer
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$G$-Force on falling object?

I'm trying to understand how G-Force is calculated, specifically with drop tests but also generally. If an object is sitting on a table it has a G-Force of 1. i.e. it has 9.81m/s^2 of acceleration ...
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1 vote
1 answer
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Effect of the Sun on the motion of bodies on the Earth

Does a body at the surface of the Earth fall at a slower rate when the Sun is at its zenith (that is when the side of the Earth that the body is on is turned towards the Sun and the body is directly ...
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Mass of a free falling object [duplicate]

What does General Theory say about the mass change of a freely falling object in a gravitational field? That is, does its mass change as the velocity increases? And, similarly, does the mass of an ...
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Falling into a Schwarzschild black hole in a rocket. Is my description correct?

Let's assume the classical Schwarzschild solution with no quantum effects and evaporation. So, we crossed the event horizon in a rocket. We find ourselves in a cylindrical space, with the nose of our ...
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Why isn't my final velocity negative in a body falling from a height?

Let's say we have a ball and we dropped it from height $20 \;\text{m}$ Case 1: Taking downward direction as positive $$v^2 = u^2+2as$$ $$ v^2 = 0 + (2)(10)(20) $$ $$ v = 20 \;\text{m/s}$$ Nothing ...
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Why don't freely falling bodies stick?

Bodies freely fall when dropped from a certain height. But they also have their mutual gravitational forces acting on each other. For small bodies I suppose the effect wouldn't be noticeable, but if ...
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How gravitational time dilation affects free-fall time

Consider a point-like planet having a large mass $M$ and two small point-like objects with masses $m_1<m_2$. Drop down each of them separately from distance $d$ on the planet, let $T_1$ and $T_2$ ...
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Velocity of bullet-block system

If a bullet is fired at a certain speed and hits (and is embedded on) a block at the edge of a cliff causing it to fall, will the initial velocity of the bullet-block system have any effect to the ...
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1 vote
1 answer
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The behaviour of acceleration of a ball in motion

I have a few doubts on how the acceleration of a ball works when we throw it up in the air, In my mind, I could imagine it in some different "real world" cases, So I am listing them all down,...
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1 vote
1 answer
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Intuitive explanation for the second solution. Projectile problem [closed]

Take the classic problem of a person standing on a high building/cliff and throws an object which follows a parabolic path to the ground. Solving this problem gives two solutions for the time in which ...
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