Questions tagged [free-fall]

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2
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3answers
69 views

Why masses connected by via a string have same accleration?

The system is in equilibrium, and the following discussion occurs after spring-1 is cut. Now, as soon as spring-1 is cut it is clear that the spring force acting one M due to spring-1,will be zero ...
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2answers
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Masses connected via string

Both the bodies are falling in gravity and as indicated by the picture and each body has a different mass QUESTION-1(Direct question) From the picture if the two masses were previously connected via ...
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1answer
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(BASIC) How do I solve this free falling question?

If someone could just show me how to solve part A, I think I can try the rest on my own. Here is the question: A model rocket is launched straight upward with an initial speed of 47.0 m/s. It ...
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3answers
121 views

Is the frame of elevator Preferred over the frame of ground? [closed]

When an object is thrown upward with some velocity then it doesn't fall towards the earth until the given velocity becomes zero. Now imagine the case given in the figure There is a question in my ...
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4answers
186 views

Difference between gravitational field strength and acceleration of free fall

Before I ask my question, I want to make it clear that I am aware that the field strength is the property of the field while the acceleration of free fall is a property of a mass falling in a vacuum ...
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1answer
45 views

Weightlessness during free fall and in free space, are they same?

Einstein's thought of a person under free-fall and when suspended in free space with no forces acting, will feel the same way. On Walter lewin's lecture on free fall he told free fall is when only ...
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2answers
85 views

Why is the moon in free fall? Isn't there a centrifugal force acting on it? [duplicate]

An object is in free fall when the force acting on it is exclusively gravitational. But why then is the moon in free fall? Isn't there a centrifugal force acting on it?
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1answer
62 views

Help me to envision a man falling towards a black hole with all of the time dilation involved

I'm standing at a safe distance from a black hole and I'm in an Earthlike time frame of reference. Through my telescope I see a man starts to fall towards the black hole. I have looked at this ...
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1answer
43 views

Motion of ball (air viscosity concerned)

Suppose a ball of mass $m$ is thrown vertically upwards from the ground. I understand that the speed-time graph would be somewhat like a distorted parabola. But what about the velocity- time graph (...
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2answers
174 views

How would a rope around Earth fall? [duplicate]

I have searched and saw a similar question but i dont know if it's exactly the same. If I had a rope around earth, let's say a few meters above (and supposing a flat surface, and suddenly dropped it ...
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1answer
39 views

How to find collision distance or impact time [closed]

I wanted to calculate the impact force of some falling object Let's assume this object has: $85kg$ mass the cross-section area: $0.75m^2$ (if that's necessary) Speed of $42.64m/s$ when it reaches the ...
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0answers
55 views

Free falling into a black hole: time to the singularity doubt!

I have trying to get a more precise insight into the calculation of the time to the singularity of a test mass into a non-rotatic uncharged black hole. Prelude: the lagrangian for a massive particle ...
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4answers
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Difference between Free Fall and Constant Velocity

We know that astronauts in the ISS feel "weightless" because they are in a perpetual free fall. The earth's gravity is the only force acting upon them, and it is accelerating them towards ...
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3answers
99 views

Why don't we consider the change in $g$ while determining the acceleration of a free falling object?

$$F=mg$$ Why is the acceleration constant? Shouldn't it change as it is thrown upward as the distance from the earth increases.I know the effects would be very negligible but is there any equation to ...
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3answers
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Period of a pendulum in free fall

Let's say I have a pendulum hanging from a bar that's fixed to the wall of an elevator. Assume that there's no air or anything inside the elevator, that the string of the pendulum is very light and ...
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1answer
81 views

I was researching on time travel and got an idea. Is free fall a case of time travel?

A person standing in a huge lift which is free falling. Observation: for that person gravity will be relatively zero. As we know the weaker the gravity is the faster time flows and stronger the ...
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3answers
63 views

Are falling objects harder to push compared to objects at rest

While an object is still in the air falling under the influence of gravity, does it take greater force to push or steer it to the side compared to when the object is in a state of rest?
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1answer
37 views

What happens to inertia of a free-falling object once one point is anchored?

The question comes from writing an oversimplified version of a physics in a 2D world as a computer simulation. I know that I can make something that looks not too horrible, but it'd be great to use ...
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2answers
37 views

Why do we feel weightless on zero G planes? [duplicate]

I've heard of zero G flights, but why exactly do we feel weightless when we are in them?
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2answers
72 views

Free Fall with Drag and Varying Air Density

I am trying to plot a graph in Excel describing a free fall of an iron sphere dropped from an altitude of 12 km, while taking into account the different levels of air density affecting the drag. The ...
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2answers
131 views

Is it proven that Brian Greene is correct about if you jump out of a window it is the Earth that rushes up to hit you? [closed]

https://m.youtube.com/watch?v=HneFM-BvZj4 (excerpt from the 2014 World Science Festival Program Dear Albert. Actor Alan Alda and physicist Brian Greene discuss Einstein's relationship with the "...
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4answers
257 views

How can there be acceleration but no velocity at instant of maximum height when object projected upwards? [duplicate]

When we project an object vertically upwards its velocity at maximum height consider to be zero but still, it has acceleration due to gravity i.e $9.8\mathrm{m/s^2}$. But mathematically we know that ...
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1answer
37 views

Difference between Gullstrand-Painlevé (GP) time coordinate and proper time $\tau$

The GP coordinates version of Sch. metric uses a new time coordinate, t', which is the time read from a free-falling clock that was dropped from rest at large r and falls past the event we're ...
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1answer
35 views

Why do we ignore the change in kinetic energy of the Earth when applying conservation of energy to the ball-Earth system?

Take the ball-Earth system where the ball is being held above the earth a height $h$ from the ground. If we apply conservation of momentum to the system, we can say that $$ \Delta P = 0 $$ $$ \Delta ...
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3answers
817 views

How does the Equivalence principle explain “what goes up must come down”?

Apologies if this is a dumb question, I am mostly self-taught when it comes to physics. I recently came across this video by PBS Space Time (Is Gravity an Illusion?) which talks about the Equivalence ...
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0answers
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Why does the mass of small objects not cause them to “pull” Earth towards them as slightly different speeds, as they fall to Earth? [duplicate]

Debate over dinner: we read on Wikipedia that objects fall at the same speed towards Earth regardless of mass. Then we remember seeing on TV ages ago an astronaut dropping a feather and bowling ball ...
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0answers
28 views

What is the formula for finding the maximum speed a 1kg mass would reach going towards a larger Mass $M$ starting at a relative speed of zero? [duplicate]

If all that exists in the universe were two masses (one with mass 1kg and the other with mass $M$) what is the formula for the maximum speed they would have relative to each other right before impact? ...
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3answers
107 views

Why does a person float rather than staying in the elevator's floor in a free fall?

Many people have asked online why does a person float on a free falling elevator in earth. But my question is why doesn't a person just stay in the elevator's floor when the elevator is in a free fall?...
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3answers
67 views

Does the object have acceleration in the tangential direction of the path? [closed]

Objects thrown horizontally fall freely along the path of the parabola. Does the object have acceleration in the tangential direction of the path? I think it is, but someone told me it was not. He ...
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0answers
23 views

Bernoulli equation under free fall in inertial frame

If a cup of water with a hole on the side of the cup, then there would be water streams out through the hole. And it could be calculated by using Bernoulli's law. However, if the cup with water and ...
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3answers
115 views

Would lifting dumbbell in free falling lift be easier or harder?

Would it be harder to lift a dumb bell in free falling lift, where the dumbbell is falling with us or would it be easier?
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1answer
31 views

Calculating the distance crossed by a ball under changing gravitational acceleration [duplicate]

Suppose a ball of finite mass is taken to such a height in space that the gravitational acceleration decreases significantly. Now, as you let go of the ball, it should head straight down towards the ...
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2answers
85 views

If two identical balls were dropped from the same height, but one of them was given a push to the side also, which would hit the ground first and why? [duplicate]

I was wondering if two identical balls were dropped from say, 10 meters, but one of them was given a push to the side whilst dropped, which would hit the ground first and why? Would the ball that was ...
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8answers
855 views

What's wrong in stating that equal gravitational forces act on two identical masses at different heights, as they have the same acceleration $g$?

This might be stupid but I need an answer. Newton's second law stated that the force exerted on a body equals the mass of the body times the acceleration of the body. And the law of gravitation ...
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3answers
122 views

Can Bob be in the same reference frame as Alice while freefalling in gravitational fields of different strengths

Alice and bob, while in a common inertial reference frame, synchronize watches so that they tick at the same rate. Alice moves to an altitude X above a large point mass and maintains her altitude by ...
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2answers
53 views

Neutral buoyancy and free fall

Is an object that is neutral buoyant the equivalent of the same object in the microgravity (free fall) of the International Space Station? If a pingpong ball floating on top of still water in a basin ...
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6answers
456 views

Are satellites doing free fall?

I was told that satellites are doing free-fall. But I don't think so, I think, assuming that the satellite is moving at a constant speed in a circular motion, the satellite does not do free-fall ...
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7answers
2k views

Cause of weightlessness [duplicate]

I'm a first year engineering student who is new to physics, so I apologize if my question is stupid. But in our statics course we are using the book "Engineering mechanics: statics" by R.C. Hibbeler ...
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1answer
29 views

Can accelerating spaceship somersault in space?

I was watching a space shuttle performing a pitch manuver in free fall, then I imagine a spaceship travelling with a constant acceleration in space trying to perform pitch manuver is it possible while ...
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1answer
82 views

Strain in a freely falling body

I wanted to know if there would be any extension in a freely falling body due to gravity . I know that a rod tied to the ceiling at one end will show an extension $MgL/2AY$. But if the same rod is ...
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1answer
58 views

Free fall with added deceleration [duplicate]

My question is about free fall from an airplane. Lets say your seat detaches from the plane and you follow a standard free fall. $$v^2=v_0^2+2g\Delta x=\sqrt{0+2\cdot 9.8\,\mathrm{m/s^2}\cdot 10000\,\...
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1answer
75 views

Free fall and gravitational waves

If you take the Earth-Moon system, from what I understand, the Moon for instance is in free fall towards the Earth-Moon center of mass. However Einstein's equivalence principle says that a body in ...
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1answer
108 views

Is the radial two-body problem solvable?

Is the radial two-body problem solvable, i.e. does the differential equation $$r''(t) = 1/r(t)^2$$ have an analytic solution? If it does, what is the solution? And if not why does everyone say that ...
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5answers
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Einstein's quantum elevator in a vacuum

If Einstein was in an elevator in free-fall in a vacuum and in his upturned hand was a miniature elevator containing a miniature Einstein who had a miniature elevator in his hand and so on in ever ...
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0answers
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Accuracy of power series solution of the one-dimensional two body problem

I regained interest in solving the one-dimensional two-body problem. It is that one wishes to determine the location of two point masses only under the influence of gravity. I assumed that neither ...
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1answer
49 views

Prove that the height swept by the ball in the last second is $5 m/s$ [closed]

I was studying kinematics and came across the following observation: every ball thrown upward with a speed greater than or equal to $ 10m/s $ will travel 5m in the last second of movement to maximum ...
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1answer
133 views

Proper Time for Free Fall into a Schwarschild Black Hole [closed]

In the solution to the question here, they define the proper time for free fall into a Schwarschild black hole as $$ \Delta \tau=(2 / 3) r_{s}\left(r / r_{s}\right)^{3 / 2} $$ but they don't provide ...
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2answers
65 views

What would happen to our sense of gravity if there was a massive object near Earth?

What would gravity feel like at different points on Earth if there was a super massive object near Earth? I know it would depend on the mass of the object, but what I'm wondering is could there be a ...
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3answers
133 views

Photon and free fall

I have questions in 2 scenarios regarding this. Lets say according to an observer P at rest with respect to the earth, me & my friend start at the same time & at the same height to free fall ...
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1answer
686 views

What would happen if you drop two objects of the same shape and size but different mass in Earth's atmosphere?

The question of letting two objects fall in vacuum and the effects on gravity is discussed on this site including questions like the gravitational pull of the objects towards each other, the Earth's ...

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