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2
votes
1answer
55 views

Why can't we feel acceleration under free fall? [duplicate]

It's a common experience when we are in some vehicle like a car being accelerated we can feel the "invisible push/pull" or acceleration caused due to the change in velocity I assume we can always ...
-2
votes
0answers
29 views

Calculation of stone dropping [on hold]

A stone dropped from a building of height $h$ reaches the ground after $t$ seconds in the air. From the building top, if two stones are thrown, one upwards, the other downwards, with same velocity $u$...
-1
votes
1answer
41 views

slippery slope facts of spherical and plane object [closed]

Imagine a slippery slope and from the top of the slope I threw two object one is spherical stone and the other is plane box. Why the stone would reach the bottom by rolling randomly where the box ...
4
votes
2answers
274 views

I know that free fall in vacuum is independent of mass. But what happens in air?

Pardon me if this sound somewhat trivial to some of the highly qualified users here. So I know two objects will fall at the same rate if they are in absolute vacuum, so what I'm assuming is that the ...
0
votes
1answer
45 views

g force when freefalling on different planet

My understanding is that g force is apparent weight/normal Earth weight, and is calculated by a+g/g where g=9.8. Now, apparent weight is the total force exerted on an object by its support, which is ...
0
votes
2answers
53 views

Accelerated frames conceptual doubt [closed]

This thing has baffled me for a very long time and therefore I had to ask it here. I was thinking about accelerated frames. Lets assume I am sitting in an elevator going upward with some acceleration ...
-3
votes
1answer
46 views

Who will feel more pain when jumping from a height, a tall man or a short man? [closed]

Whether the impact on a tall man is greater than a short man when he jumps from a height?
0
votes
2answers
68 views

Simple mathematical model for a bouncing ball

I started coding a physics program that simulates gravity - specifically a bouncing ball - and I've already learned a lot researching the topic but the bounce still doesn't look quite right. I need a ...
4
votes
0answers
39 views

Schwarzschild metric, speed of ball as measured by observer who catches the ball, just before ball is caught? [closed]

Inspired by this question here. The Schwarzschild metric, describing the exterior gravitational field of a planet of mass $M$ and radius $R$, is given by$$ds^2 = -(1 - 2M/r)\,dt^2 + (1 - 2M/r)^{-1}\,...
-1
votes
1answer
37 views

Freefall and Weightlessness [closed]

If a boy in the elevator drops a ball, does the ball fall onto the floor of elevator? Actually I have a confusion with this question. Is the elevator at rest or in motion. And if the elevator is in ...
-3
votes
1answer
75 views

Need motion equations for falling ball for simulating [closed]

I am currently M.S student in artificial intelligence(A.I) and working on my thesis on reinforcement learning, which robot should learn by itself how to control a quadcopter. Long story short, I have ...
1
vote
1answer
62 views

Conditions for free fall

What are the conditions at which free fall occurs? If a body is falling freely under the effect of gravity only without external resistance, the motion is called free fall. This definition gives me ...
2
votes
1answer
48 views

An example of a theory that respects the Weak Equivalence Principle but violates the Einstein Equivalence Principle

The Weak Equivalence Principle has any one of the following forms: the inertial mass is equal to the gravitational mass there exists a preferred class of trajectories through spacetime, known as ...
0
votes
0answers
22 views

Do all objects free fall at the same rate regardless of their mass? [duplicate]

Is it true that all object will fall at the same speed in vacuum irrespective of their mass because the acceleration due to gravity of Earth is 9.8 m/s2. Then what happens to the gravitational force ...
0
votes
1answer
52 views

Deviation of free falling objects (Coriolis effect) using conservation of angular momentum

I read this pdf on non inertial frame, in particular I have a question on the deviation of free falling object due to Coriolis effect. Consider a ball let go from a tower at height $h$. The ...
1
vote
2answers
96 views

Difference between gravity and standing on a platform accelerating upwards at 9.81 m/s^2

So, according to Einstein's theory of general relativity, gravity is not a force instead it is a consequence of objects with mass deforming spacetime, right? And so, according to him, there is no ...
0
votes
0answers
32 views

What is the equation for the position of a falling body as a function of time? [duplicate]

I know that near the surface of the earth a projectile's position follows a parabolic curve in function of time because the acceleration is constant (about 9.8 m/s2). However, acceleration ...
0
votes
2answers
47 views

Parachute Model

Can you tell me if this model is correct or not? [assuming drag is linearly proportional to the velocity] Considering y-axis vertical and x-axis horizontal,with y positive upwards: 1) $F_y=-mg-kv_y=...
1
vote
4answers
95 views

Gravity and force

I have a question and am not able to answer it. Suppose you drop two objects from different heights. They are exactly the same shape, size and weight. Now we know that the gravitational acceleration ...
1
vote
3answers
176 views

Free Fall with Air Resistance

Can somebody help me understanding why when free falling the force on the vertical axis is F= -mg-kv, where k is the constant of air resistance and v the velocity? Suppose the vertical axis is ...
1
vote
1answer
57 views

Parachute jumping with air resistance

I need to write down a model for a man parachuting from a plane at a height h above the ground, having a velocity Vplane. I've had a look at many models online and they all start saying that F=ma=-kv-...
1
vote
0answers
11 views

How to calculate force on impact after free fall in water [duplicate]

I'm trying to calculate the force of a man falling from a bridge into water below. Thus far I've calculated everything except for the force he would experience hitting the water. Would I need to do ...
0
votes
2answers
58 views

Free falling object with air resistance, what's the velocity as a function of time?

So, I'm looking into how velocity can be represented as a function of time when the air resistance is also function of velocity. The force of drag is $$ F_d = C||\vec{v}||\vec{v} $$ where $C$ is an ...
0
votes
2answers
65 views

How can I clarify the difference between free falling and Newton's law?

After I have viewed two experiments the first about Newton's law which involves a brick block and feather letting them fall one time in a vacuumed room they fall at the same time and another time in ...
2
votes
4answers
80 views

Introductory physics: first second of free fall

While doing my physics homework I encountered an acceleration problem that I've been unable to solve. Here, is the data table of the objects motion. At 1 second, why does the "Dist-meters" slot of the ...
-1
votes
2answers
97 views

Will I die from a 50-foot fall? [closed]

Sorry if I didn't ask this in the right place, but... Will I die from a 50-foot fall? What are the chances of survival? I know this is more of a biology question or something, sorry :(
0
votes
1answer
66 views

Application of Mean Value Theorem to Law of Universal Gravitation

I'm not terribly well-versed in physics, so forgive me if this is trivial. Supposing an object hovers $6*10^5$ metres above Earth's surface, calculate its impact speed after falling to earth's ...
1
vote
1answer
63 views

Will a cyclist be able to pedal during free fall?

Assume that he is seated on the cycle and his waist is tied to the seat.
0
votes
3answers
113 views

Reach @ jumping from one building to another

Let's assume I'm in the rooftop of a building (Building A) and want to jump to the rooftop of another building (Building B). Forget about injuries... is just hypothetical. Building A has a height of ...
1
vote
0answers
51 views

Hammer will fall faster than the feather on the moon. 10 second thought experiment! [duplicate]

Please explain where my logic is wrong. a) Ignoring air, the same bowling ball will fall faster on Earth than on the Moon. b) Now, for the feather and hammer on the Moon, reverse your point of view ...
0
votes
1answer
54 views

Why will you float in free fall with 0 relative acceleration?

Imagine you are in an elevator that is falling freely to the surface of the earth. You begin to float. However you and the elevator have equal acceleration. Why is it that you begin to float with ...
0
votes
1answer
23 views

Equation for Turning Projectile

I'm trying to cook up an equation that will give me position for a projectile which operates in the Newtonian Domain. So a the fall equation is: $$\mathbf{p_t} = \frac{\mathbf gt^2}{2} + \mathbf{v_0}...
2
votes
1answer
159 views

Infalling light signals seen by a free falling observer

In this question/answer Does someone falling into a black hole see the end of the universe?, it is stated that an observer free falling toward/into a black hole will not see the end of the Universe ...
1
vote
2answers
89 views

How does general relativity explain the impact force after radial inward fall toward Earth?

I understand that, in the context of the Schwarzschild spacetime (General Relativity), a radially inward falling observer follows a time-like geodesic with zero four-acceleration. There are no forces ...
2
votes
1answer
247 views

Do free falling observers see gravitational blueshift?

Observers at rest in gravitational fields will see infalling light signals as blueshifted. Do inertial observers in free fall in a gravitational field see the same shift? If someone is standing on a ...
-1
votes
1answer
48 views

Calculate the distance of a falling object and terminal speed [closed]

I have a homework problem that I would like to verify that I am doing it correctly. If anyone could help me see where I'm going wrong with the steps, I would really appreciate it. (a) Consider a ...
0
votes
1answer
44 views

Solve the inverse function of the solution to a varying acceleration problem ODE

Suppose there are two positive charges $A$ and $B$, both with equal mass $m$ and the same charge quantity $q$. The initial distance between $AB$ is $R$; and the initial velocity of $B$ relatively to $...
0
votes
1answer
46 views

What's the average speed (along $z$) and the average position (along $z$) of an object in free fall?

I'm looking to calculate the average speed (along z) and the average position (along z) of an object in free fall. The initial instant is $t_0$ and we have: $z(t=t_0)=z_0$ $v_z(t=t_0)=v_0=0$ I ...
0
votes
0answers
39 views

Galileo proved wrong? [duplicate]

Galileo stated that objects dropped from the same height will hit the ground at the same time, that the rate of gravity is constant for all objects no matter the mass. But I think there is a flaw in ...
0
votes
1answer
97 views

Mimicking Free Fall

I was thinking about this situation with a friend of mine, and we had opposing views: Suppose you have a frictionless table with mass M resting on top. You attach a chain to the mass M, a chain with ...
2
votes
2answers
80 views

Why is it easier to drop on to a downslope?

On a bicycle, why is it easier to land from a drop or jump on a slope going downwards than landing on a flat surface or on an upslope? I've already heard answers such as "because that's how a bike ...
-1
votes
1answer
585 views

Two objects at different heights, would they be traveling the same speed?

If I were to drop an object at a height of 15 feet, then another object of the same mass at 20 feet, would both objects be traveling at the same speed? What would be the speed of which they are ...
0
votes
2answers
87 views

Derivation of a kinematical equation [duplicate]

My question is, we can calculate distance of free falling objects with the equation of $d = \frac{1}{2}gt^2$ where $d$ is distance in meter, $t$ is time in seconds, but I wonder how we achieved this ...
3
votes
0answers
166 views

Free-Fall Lab Help - Getting weird results

So, I am doing a free-fall lab for my physics class. We got the values and I have the results here(we used a infrared photo-gate). Basically, we have a brass cylinder and a wood cylinder. Each are ...
0
votes
1answer
54 views

Physics Problem: Falling Rocket [closed]

A rocket, of mass $M = 40kg$, falls vertically with a speed of $60 m/s = v_0$ and explodes in two fragments of the same mass when it's at $H=2km$ from the ground. Immediately after the explosion one ...
1
vote
1answer
110 views

Free fall and gravitational time dilation

An observer A at rest in a gravitational field has some amount of time dilation relative to an observer B far away from the gravitational field. Would the clock of an observer C in free fall at the ...
54
votes
6answers
7k views

Can a Skydiver Land On a Large Slide and Survive?

Please forgive my lack of artistic ability, but here's my question: Consider that a skydiver, without using his parachute, were to fall exactly parallel to a giant curved slide that starts at $90\,^\...
2
votes
2answers
84 views

Will the gravitational pull of air affect the falling rate of an object?

After looking at this question: Don't heavier objects actually fall faster because they exert their own gravity? A thought occurred to me that due to the increased gravitational pull of the ...
34
votes
8answers
13k views

Why does a free-falling body experience no force despite accelerating?

Note: For the purposes of my question, when I refer to free fall assume it takes place in a vacuum. From my (admittedly weak) understanding of the equivalence principle, falling in a gravitational ...
0
votes
1answer
124 views

Probability Density of a freely falling body

The following question has been taken from David J Griffith's Intro to QM. This is not my homework! :D Suppose I drop a rock off a cliff of height $h$. As it falls, I snap a million photographs, at ...