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0
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2answers
45 views

Accelerated frames conceptual doubt

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
39 views
18
votes
8answers
10k views

Would it help if you jump inside a free falling elevator?

Imagine you're trapped inside a free falling elevator. Would you decrease your impact impulse by jumping during the fall? When?
8
votes
6answers
3k views

Gravity - What happens when two objects of unequal masses fall freely towards the ground? (Revisited)

The common perception regarding what happens when two objects of equal sizes but unequal mass are allowed to fall freely towards the ground is that - both the objects make contact with the ground at ...
1
vote
3answers
235 views

Does center of mass affect how an object falls?

Suppose you drop an object which has two ends, of which one is heavy and the other is pretty light. Will the object fall with its heavier end downward or with the lighter one? Why does it happen?
0
votes
1answer
44 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 ...
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}\,...
0
votes
2answers
53 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 ...
-1
votes
1answer
31 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
73 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
4answers
4k views

When an object moves downward, is its height negative?

The question is: A ball is thrown directly downward with an initial speed of 8.00m/s from a height of 30.0m. After what time interval does it strike the ground. So I went through the problem ...
1
vote
1answer
50 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
47 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 ...
149
votes
9answers
37k views

Don't heavier objects actually fall faster because they exert their own gravity?

The common understanding is that, setting air resistance aside, all objects dropped to Earth fall at the same rate. This is often demonstrated through the thought experiment of cutting a large object ...
0
votes
0answers
21 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 ...
1
vote
2answers
92 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
31 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 ...
1
vote
3answers
163 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 ...
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
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
57 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
3answers
203 views

What physics concepts support the observation of the book and paper falling together?

you place a sheet of paper on a book, it falls with it rather than being separated & slowed by air resistance. What physics concepts support the observation of the book and paper falling together?
0
votes
2answers
64 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
77 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
91 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 ...
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 ...
1
vote
1answer
106 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 ...
2
votes
1answer
242 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 ...
36
votes
6answers
8k views

Which ball touches the ground first?

This is a very well known problem, but I can't find an answer in the specific case I'm looking for. Let's consider two balls : Ball 1 weighs 10 kg Ball 2 weighs 1 kg Balls have identical volumes (...
1
vote
1answer
60 views
0
votes
3answers
107 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 ...
6
votes
4answers
3k views

Force of an impact on water

Today, at the Brazilian news, I heard that a men fell from a cruise into the sea, from a height of 50m, and decided to see if he could have survived. I took his weight for being 80kg. I did $V^2=V0^...
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 ...
2
votes
1answer
155 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 ...
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}...
1
vote
2answers
86 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 ...
-1
votes
1answer
47 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
45 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
90 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
79 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
528 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 ...
3
votes
0answers
157 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
53 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 ...
54
votes
6answers
6k 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\,^\...