# Questions tagged [free-fall]

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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 $T_2$ ...
1answer
19 views

### 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 ...
1answer
36 views

### 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,...
1answer
55 views

### 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 ...
0answers
38 views

### Stokes law, falling body problem: what sign?

This is quite a basic question, but it gives me just headaches, after I was really thinking about it: By equilibrium a falling body in a viscous medium will ultimately have the following forces ...
0answers
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### Weightlessness and free fall on oil drop experiment

Suppose I have an oil drop which is negatively charged placed in a box with the bottom of the box negatively charged. When this box and oil drop is placed on a table where the box is stationary, the ...
1answer
34 views

### How no Contact forces on objects with stacked on top of each other

How can there be no contact force between two bodies stack one top of another during freefall if they are in contact?ho
3answers
40 views

### Free fall and contact force

If two bodies are stacked on on top of other and in free fall and there is no contact force how come they remain in contact ignoring drag. Secondly if two object were at rest say on table and table is ...
1answer
15 views

### Contact force and intermolecular distance between two objects during free fall

I am a bit confused. When two objects are in a free fall such that when released to free fall they were one top of another, will there be any contact force between the two objects and will there be a ...
2answers
63 views

### The effect of pressure on the height of the first bounce of a volleyball [closed]

I'm currently working on an experiment and the first step is to come up with a hypothesis, which is based on a physics proof. The experiment involves droping a volleyball from a fixed height and ...
0answers
32 views

1answer
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### 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(...
1answer
62 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 ...
0answers
20 views

### 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 ...
0answers
54 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 ...
2answers
94 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 ...
0answers
34 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 $q_2$ ...
3answers
37 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 ...
1answer
87 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?.
1answer
30 views

### 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 ...
0answers
33 views

### 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 ...
1answer
45 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. ...
3answers
58 views

### 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 \...
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 ...