All Questions
Tagged with gravity kinematics
56
questions
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How much time does it take for an object to fall from space? [closed]
Let's say there's an object of mass $m$ in space, $h$ meters away from the surface of the Earth. $h$ is large enough that $g$ cannot be assumed to be constant. The acceleration varies according to ...
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3
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57
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Work energy and power [closed]
I saw this in a textbook and I want to confirm if it's true
If a body of mass m rolls down an
inclined plane of height h and length l (hypotenuse), the work done is mgh. It is the vertical height of ...
1
vote
1
answer
44
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Defining Free Fall: Does Gravity Need to be the Sole Force Present?
Can a scenario be considered free fall in physics if the work done by forces other than gravity is zero, but those forces are still present? Or is it necessary for gravity to be the only force present ...
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3
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174
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Need help solving a projectile motion problem: finding the angle for a thrown ball to intersect with a vertically falling ball
The problem states that a ball is dropped from rest and falls under the influence of gravity (neglecting air resistance). At the same time, another ball is thrown with an initial velocity of v0 from a ...
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2
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41
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Ramp friction error: Answer seems to depend on coordinate system
I am a junior level mechanical engineering student, and have taken physics, statics, dynamics, etc. so I know how to do this problem, though something seems to be tripping me up.
Given a standard ramp ...
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2
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175
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Angle of projection for the minimum time of flight for a given range
If a projectile has to cover a fixed range under gravity, then what should be the angle of projection for the total time of flight to be minimum?
The initial and final point of the projectile are both ...
- 33
1
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0
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33
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Difference between geodesics on surfaces and paths under gravitiational fields
Sorry for the maybe silly question, but I'm a math student and I'm not able to find the answer to this question from the physics point of view.
Let us suppose that a ball is set in a non equilibrium ...
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86
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An object falling from very far would have varying acceleration, how can that be accounted for?
I want to have a function that describes where a falling object is.
Like this one:
h(t) = -g*t²/2
But this one is for the usual close to the surface case, where there is no variation of gravity due to ...
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4
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125
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Initial velocity of a body when the distance travelled by it in the last second before reaching its maximum height is $5\ \textrm{m}$ [closed]
I stumbled upon this problem recently, and it has been haunting me for more than a day at this point. The question is as follows:-
When a ball is thrown up, it reaches a maximum height of $h$, ...
- 103
1
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1
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24
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How would look like the distribution of warmer and colder air molecules inside a spacestation with no gravity?
How would look like the distribution of warmer and colder air molecules inside a spacestation with no gravity? Also how would look like the form of the fire when somebody lights up a piece of paper?
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174
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Inertia of an elevator
Imagine a situation where we have a relatively light empty elevator moving up at a pretty high constant velocity say something above $10\ m/s$, just so that it has a considerable amount of momentum ...
1
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5
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162
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Conflicting intuitions about free fall
So I just started studying physics recently, and I came up with a question that I'm not sure how to solve, and I think it may be because of some fundamental misunderstanding. I don't want anyone to ...
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2
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3
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335
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Should the stars of a relativistic binary system have tangential acceleration?
Should the stars of a relativistic binary system have tangential acceleration?
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1
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1
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123
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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,...
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2
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501
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Gravitational Force & Normal Force
Imagine a moving ice-block on an extremely smooth (i.e. friction is zero) and circular, rogue planet devoid of an atmosphere. Assuming that the planet in question is far away from any (massive) object ...
- 413
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1
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543
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State space of free falling object is time variant?
In the case of a free fall object, if $h$ denotes distance from floor and $v$ the speed, then, given an input $U = g$, and $X=[h \quad v]^T$ and $\dot{X}=[\dot{h} \quad \dot{v}]^T$, I found that the ...
8
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6
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1k
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How to find the falling time of an object when acceleration is not a constant? [closed]
Let's say we are throwing an object from the surface of the earth, this object reaches 70,000km with initial velocity of $10713 \mathrm{m}/\mathrm{s}$ until it reaches the peak high , the g value at ...
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0
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1
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162
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Gravitational field of a moving object
Here's a simple scenario:
Let's say, that there are 2 stationary planetoids of equal mass on the Earth's orbital motion path, placed at equal distances from Earth just like on the image below:
Will ...
1
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1
answer
2k
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How to simulate orbits?
I was trying to code a simulator of a solar system, but I cannot find out the orbit trajectory equation. I have simulated my orbits with perfect circles by using the $\cos \alpha$ and $\sin \alpha$, ...
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2
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119
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How to solve this long distance projectile problem? [closed]
A projectile is fired horizontally from the top of a mountain of height 'h' at a very high velocity. The projectile almost completes one revolution around the earth and crash lands at the bottom of ...
- 337
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1
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171
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What is rate of change of Earth's gravity (jerk, 3rd derivative of position)? [closed]
We know that gravity changes with height so there must exist a jerk. Could I know the method to find it. Does there exists jounce(4th derivative of position) for Earth's gravity?
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2
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293
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What would a graph of distance between two gravitational objects vs time look like?
Lets say there are two objects in space that are attracted to each other, and are a distance r from each other. The gravitation force between the two objects is $$G\frac{Mm}{r^2}$$ As they accelerate, ...
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2
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1
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184
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Why can gravitational acceleration not be detected by experiments
I was doing research into how $G$ forces are calculated, and I was told that they show all acceleration that can be "sensed" by humans (i.e. all non-gravitational acceleration).
This ...
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4
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1k
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Acceleration due to gravity during its journey up and down
When we throw an object up into the air, ignoring air resistance, etc, we define acceleration to be -9.8 m/s^2. When it goes down after its journey up, like a parabola, do we define the acceleration ...
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1
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114
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Beads on a frictionless frame of wire [closed]
I was doing a physics problem and though I have the solution, I have derived a general result which I would like to get verified. I will state the problem here :
Two beads q1, q2 of equal mass m can ...
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1
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357
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Angular acceleration of ball when falling [duplicate]
Why is it assumed that angular acceleration is 0 when a ball is midair after rolling off a surface with constant velocity?
-1
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1
answer
39
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Vertical motion [closed]
Ball $A$ is thrown vertically upward from the top of a $30$ m high building with an initial velocity of $5$ m/s. At the same instant, another ball $B$ is thrown upward from the ground with an initial ...
0
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1
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296
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Path of an object in gravitational field [duplicate]
How do you prove that path of a satellite or a planet is a second degree curve? In other words, how do you prove Kepler's law which states that planets move in elliptical paths?
1
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3
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557
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What is the effect of acceleration due to gravity on horizontal acceleration?
The question is the following:
An object accelerates from rest to $100\,\mathrm{km}$ per hour in $4.0\,\text{seconds}$. What fraction of the acceleration due to gravity is the car's acceleration?
...
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451
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How does an object gain energy when it enters a potential field?
Conservation of energy says total change in energy is $0$.
Let's assume a small object is in outer space (maybe like a football).
It moves towards a planet (assume planet has no atmosphere for ...
12
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1
answer
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How does this magnetic toy work?
A nephew of mine has this toy called "Gravitrax". It is basically a track building kit - you can build various tracks for iron balls which go through the track thanks to gravity.
However, there is ...
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2
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97
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Distance an object has fallen given time
I am in Honors Physics, and need help understanding this:
The acceleration of Earth's gravity is 9.8 $m/s^2$, so when an object starts from rest, 9.8 $= x/t^2$, where $x$ is distance the object will ...
- 101
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1
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26
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Finding the continuous increase in speed while diving toward the ground
https://youtu.be/HJO6WuoytGA?t=39s
In this game, the character jumps from the top of the Empire State Building (443.2m), and in a fraction of a second, he breaks Mach 1 just by releasing a great deal ...
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2
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121
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total weight experienced in Five ball Cascade
An expert juggler, carrying five juggling balls, has to cross a swing bridge which has a maximum load rating of 50 kg. The juggler weighs 47kg and each of his 5 balls weigh 2kg. He believes that he ...
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2
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1
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1k
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Free fall and terminal velocity
An object in free fall is defined as one that is moving solely under the influence of gravity.
So if an object has reached terminal velocity(force of gravity is cancelled out by upwards force of ...
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4
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2k
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What is the evidence for the existence of gravity [closed]
I have recently been wondering that what good evidence proves the existence of gravity (besides the Cavendish experiment).
I would like straightforward answers that are on point. I will be willing to ...
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2
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Calculating height of a ball formula based on bounce
I'm trying to figure out a formula for the new height of a ball, up until it stops bouncing.
The time iteration between each could be for example one second; and gravity of course would be 9.8
I've ...
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5
answers
473
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Calculating relative distance covered
Two balls 'A' and 'B' are thrown vertically upwards with the same velocity. The mass of A is greater than that of B. We need to find which of the balls reaches a greater height (assuming the effect of ...
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2
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695
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Is the magnitude and direction of gravity on an object the same as the objects vertical velocity?
I need to make a diagram for an entry level college physics class. I need to show the magnitude and direction of gravity on a flying object and also show the magnitude and direction of the objects ...
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1
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Position / velocity / acceleration vs time graphs when falling towards a black hole
In Newtonian physics, as far as I understand it, for a small object falling towards a massive object, the graphs of position, speed and acceleration vs time look like this:
(If the massive object is ...
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1
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226
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How Do Low Kinetic Energy and High Kinetic Energy Atoms Attraction differ?
Will atoms of 2 difrent energy levels electron and/or Kinetic attract more than 2 Atoms at he same energy level? Do 2 high energy level atoms attract more than 2 low energy atoms?
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33
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In Which Position A Co-passanger should Sit On A Turning Bike
Pardon me for this very basic mechanical science question. But I just want to clear my doubt it. Whenever I sit a behind someone on a bike I get confused when the the bike has to take a sharp turn.
I ...
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Minimum Distance for "Speed of Light Approach"
I tried to calculate the minimum distance between a planet and a test mass for the mass to attain the speed of light on colliding with the planet's surface if it were released from rest at the initial ...
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35k
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When does acceleration due to gravity equal positive/negative? [closed]
For example a projectile is launched at an angle. What would $a$ in $y=vt +.5at^2$ be?
Let's say I choose up to be positive. How do you not confuse yourself whether to use positive or negative $a$?
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2
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203
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Is there a mistake in this example in my mechanics textbook?
This is a worked example in my mechanics book:
But I think this worked example is wrong. In the 6th line. shouldn't $X=4R$ as the expression for distance above the surface is $(X-R)$ and when the ...
- 2,137
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1
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48
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Shock Absorber - Bus - Not Uniform
Imagine a empty bus/lorry travelling at high speed over the "speed brake", why is that only rear seat is heaved relatively high compared to the fron seat?
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2
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2k
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Non-Constant Acceleration due to Gravity
Recently, I had the first physics lab for my university physics course. This lab was fairly simple, as we were merely using a computer and a distance sensor to graph the position, velocity, and ...
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145
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Is projectile trajectory on Earth affected by the fact that it isn't a singular point?
So in high school physics, we were told that projectiles traveled in a parabola, but Google searches have said that it's more like an ellipse, since the Earth isn't flat. However, I was thinking that ...
2
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5
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2k
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How does this shell hit the aircraft?
A fighter aircraft is flying horizontally at an altitude of 1500m
with speed of 200m/s. The aircraft passes directly overhead an
anti-aircraft gun. The muzzle speed of the gun is 600m/s.
We ...
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1
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907
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Simple pendulum and planet mass [closed]
A simple pendulum, $20cm$ in length, has the period of $2.7s$ on a certain planet. Find the mass of the planet if its diameter is $18000km$. $G=6.67\times10^{-11}Nm^2/kg^2 $
I have no idea how to get ...
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