Questions tagged [free-fall]

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Why does a body falling down follow this pattern of velocity?

I was wondering about the pattern of velocity for a body falling down with initial velocity $u= 0$ and $g = 10m/s^2$. Without using the formula , I thought : Velocity would change in this manner (...
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1answer
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Question of ball falling down.Difficulty in understanding the formula

A ball is thrown upward from the top of a tower 40m high. u = 10m/s.Find time for it reach AD. g = $10m/s^2$. Taking upwards direction as +ve and downward as -ve. u = +10m/s.$g=-10m/s^2$.s=-40. $-40 = ...
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1answer
45 views

Diffentiating a gravity field to get the radius from a planet center as a function of time [closed]

I'm trying to solve a differential equation to get the radius from a planet as a function of time during a free fall. $$ g=\frac{d^2r}{dt^2}=\frac{GM}{r^2}. $$ Is this statement true? $$ [r^3]d^2=GM(...
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1answer
60 views

Speed, acceleration, accelerating acceleration, etc. How do we know where to stop?

I am not a physicist. Suppose a body A is falling towards body B in a vacuum. We know that A's speed will increase. However, as A draws near to B, the force of gravity will increase so the rate at ...
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Displacement time graph- aerodynamic drag

In the displacement vs time graph of an object in free fall, the parabola with aerodynamic drag is much more steeper on the way downwards of the object than the parabola in which air friction is ...
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0answers
35 views

Jumping without a parachute — how much horizontal velocity can you achieve?

I am curious about the old chestnut of falling from an extreme height -- perhaps 1,000 meters or more -- and whether it is possible to convert most of the vertical velocity to horizontal, or any ...
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2answers
71 views

Calculations of Earth falling into the Sun if it suddenly stopped orbiting? [duplicate]

If the earth stopped orbiting the sun, it would be pulled by the Sun's gravity and fall into it. How much time it will take is tricky as force is inversely proportional to square of distance. So I ...
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1answer
35 views

If there is a great value of launch angle, what happens to the horizontal range?

How would you critique this answer for the question "If there is a great value of launch angle, what happens to the horizontal range of a projectile with an initial height greater than zero and ...
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0answers
31 views

When do these two point charges meet? [duplicate]

Two point charges in the vacuum (so ignore all frictions). They have opposite signs so they will move towards each other under Coulomb's force. The magnitude of their charges are $q_1$ and $q_2$ ...
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3answers
33 views

Velocity when touching ground and when fully stopping at arena

So my doubt is: my teacher told us that when a ball hits the ground, the velocity isn't 0, but I've encountered a problem that involves a ball falling (free fall) to the sand, and when hitting the ...
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1answer
77 views

Would it be correct to say that the Earth accelerates toward us when we fall?

By relativity theory, would it be correct to say that a planets surface accelerates toward us when we jump and then fall toward it? Or both (a planet and a person) do?.
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Does mass has any influence on a horizontal launch?

Really short doubt. Let's say I have 2 objects, with masses 3kg and 4kg, both are thrown horizontally with the same initial velocity, both will touch the ground at the same time right? Because g ...
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Free fall of two point particles in general relativity vs. Newtonian mechanics

In general relativity (GR) the equation of free fall of two point particles which start from rest at some finite distance $r_i$ is strikingly similar to the equation of free fall in Newtonian ...
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1answer
25 views

Pressure and bounce height of a ball

Is there a physics way to explain why higher pressure makes the ball bounce higher? It is allowed to free-fall at a certain fixed height. For different pressures, the ball bounce to different heights. ...
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3answers
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Maximum horizontal distance of a freefalling ball with one allowed bounce anywhere along its initial path?

I was washing a spoon in the sink and this question popped into my mind: If a ball is dropped from height H and is allowed a single deflection of any angle $0 < \theta < 180$ at any height $ 0 \...
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1answer
45 views

How would you go about scientifically comparing the physics of a game and real-life through gravity?

A bit of a hypothetical situation for y'all here. Let's say you want to test a video game's accurateness with regards to its physics; by seeing how closely the game's physics matches up with real-life ...
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3answers
142 views

Does gravity exert an impulse on a free-falling object? [closed]

Suppose an object in free fall travels upward from the ground with some initial velocity. Then the sum of all forces acting on it is $F_g = mg$. And suppose additionally that the object reaches a ...
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2answers
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Free-falling object: When should we consider General Relativity?

My question is related to a statement: If a pendulum is experiencing free fall, then it will not oscillate. The statement is true in the sense that its acceleration is (approaching to) zero, then ...
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1answer
190 views

Reconciling Wikipedia formulae for time dilation due to gravity and velocity

Wikipedia "Time dilation" shows the formula $\sqrt{ 1-v^2-v_e^2-v_r^2.v_e^2/(1-v_e^2) } $ where v is (perhaps) the 3D speed, $v_e$ is the Newtonian escape speed, $v_r$ is the radial speed. ...
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3answers
90 views

A question on probability and free fall [closed]

An object in free-fall drops from rest. The origin is at the starting point and the $y$-axis points downwards. The $y$-coordinate of the ball is, $$ y = \frac{1}{2} g t^2$$ The total time of flight is ...
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4answers
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Which cases $g$-force is negative $(g=-9.81m/s^2)$?

A stone was dropped into an empty well. It takes 10 sec to hit the ground. What was the velocity of the ball? So since I have to use the formula $v=gt$ I'm quite confused if g=$-9.81m/s^2$ or not? ...
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4answers
723 views

Height is compared to earth radius?

If air resistance is neglected, the object is said to be in free fall. If the height through which the object falls is small compared to the Earth's radius, $g$ can be taken to be constant, equal to $...
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1answer
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Can a single electron slide down a smooth glass incline plane?

It is said that there are detectors that can detect the impact of a single charged particle in transmission electron microscopy (TEM) that do not rely in the conversion of electrons into photons. In ...
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3answers
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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
54 views

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
44 views

(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
128 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
281 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
49 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
99 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
45 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
182 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
90 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
63 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
102 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
96 views

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
90 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
72 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
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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
89 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
137 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
354 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
40 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
36 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
838 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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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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