All Questions
Tagged with newtonian-gravity free-body-diagram
137
questions
-2
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5
answers
105
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When an object is thrown towards the sky it starts to gain potential energy, why?
I didn't think so because when an object is thrown towards the sky it already has kinetic energy and it looses it's energy due to the gravitational force of the earth.
When the object looses all of it'...
0
votes
1
answer
80
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Where am I wrong in proving that force perpendicular to motion increases speed and kinetic energy? [closed]
Lets think of a helicopter flying at some height $h$. It throws a food packet to a person on the ground from air. Let's neglect the air drag.
The food packet is thrown only with some velocity $v_x$ in ...
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1
vote
1
answer
48
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Drawing a free-body diagram for a body residing on Lagrange point $L_4$ and $L_5$
I am aware of the fact that Lagrange points $L_4$ and $L_5$ are stable equilibrium points however I cannot understand why they are equilibrium points in the first place.
Consider a Earth-Moon system ...
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7
votes
7
answers
3k
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How do objects reach terminal velocity?
I understand the basics of this principle: the force of gravity acting downward on an object becomes equal to the air resistance acting upward on the object because as the object speeds up, air ...
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0
votes
1
answer
56
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Why is hookes law not obeyed in vertical circular motion? [closed]
We know that $$T=-kx=-k(R-L)$$where $L$ is the natural length of string, so the tension force must be constant. but in vertical circular motion the tension force is not constant (via analysis of ...
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votes
1
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93
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Does Weighing machine measure normal force or gravity or both?
A weighing machine measures the normal force applied by an object.
However 2 forces act simultaneously on the machine ( normal and mg )
Under normal conditions (a=0) N=mg .
So this would mean that a ...
0
votes
1
answer
39
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Air Friction Newton III
I have question to the Newton III Law and Air Friction.
At the free Fall of a Body there is an Air Friction, which is in oppopsite direction to the Gravitation Force. In my opinion the Body pushes to ...
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-4
votes
1
answer
64
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Find the acceleration of a block sliding down on an accelerating inclined place [closed]
I don't understand the solution provided in the image. Using Newton's second law for forces along the x-axis (parallel to the inclined plane), shouldn't the equation be $ma = mg\sin \theta+ mb\cos \...
0
votes
0
answers
69
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Dynamic equilibrium of planets
We can describe statical equilibrium ( forces, moments ) in a cuboid $$ \Sigma F_x=0,\Sigma F_y=0,\Sigma F_z=0~$$ In dynamics can we describe similar dynamic equilibrium within an inertial ...
- 1,032
2
votes
2
answers
46
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Is there any effect of gravity in a vertical nonlinear spring? [closed]
I know that for a linear vertical spring, the governing equation of motion written in the presence of gravity is the same as the one written in the absence of gravity. We can either undergo a ...
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1
vote
2
answers
252
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Chain hitting a scale
a standard problem in textbooks is to calculate the force of a chain of length $L$ as it hits a scale and has fallen a length $x$. It is found to be $3gMx/L$ by the gravitational force $xmg/L$ and ...
- 139
0
votes
1
answer
96
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Confusion as acceleration seen from different angles disagree with each other
Heres the question:
Find the tension in the chord when the balls height above the lowest position is $\frac{1}{2}L$. Answer should be in terms of $g$ and $m$.
The solutions manual decided to orient ...
2
votes
6
answers
879
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If there is no gravitational force on the earth (i.e. acceleration due to gravity is 0m/s^2), will bodies in contact still experience a normal force?
My question arises from this post by Ashish Arora, where he asks: "If $g$ becomes zero suddenly, a body at rest on a fixed table will start moving away from it."
In the above question $g$ is ...
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0
votes
2
answers
72
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How can people be weightless on space station?
I had read it somewhere that on the space station, people are weightless. even though artificial gravity is created there, people are still weightless. how can this be possible if there is gravity, ...
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1
vote
6
answers
541
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How does unbalanced force ever create? [duplicate]
This question rather seems elementary but has been bugging me for a while! How does even unbalanced forces create? The main driving force of this question is Newton's third law
Let's take Free Fall:
...
- 648
1
vote
0
answers
30
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Can a thin pole break or be cog-sensitive under the influence of gravity?
When we consider such a phenomenon, what I am wondering is that the body of an object having a thin radius seems to cause the center post to be broken or the cog to be very sensitive, but why should I ...
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1
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57
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How can vertical force due to gravity vary in a column?
Non-physicist asking.
Suppose I have a tall building or column. The downward pressure on the walls near the foundations is intuitively greater than at the top of the building. Yet according to Newton, ...
- 3,006
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votes
2
answers
351
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Loop de loop free body diagram [closed]
I'm trying to understand the situation where a roller coaster goes around a loop, and we need to find the minimum speed it takes not to fall off.
What I'm not understanding is why we would set the ...
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4
votes
3
answers
256
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Could you feel your weight falling through the a tube drilled through the center of the earth?
Suppose you drill a hole through the center of the earth (assume the earth is uniform and no air resistance) and you jump in. Would you be "weightless" throughout the entire fall?
The reason ...
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2
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61
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Theoretical question about elevators [closed]
Question
Imagine we put a bascule/weighing machine in an elevator, and that elevator starts to acelerate downwards with a certain aceleration that we don't know of. Is it true that the bascule will ...
user348118
0
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3
answers
547
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Why is the normal force always perpendicular to the surface rather than opposing the force?
In the classic "box on a ramp" example, how does it know which way is perpendicular? If the normal force was opposite of gravity, the force being applied, it would still constrain the box ...
2
votes
1
answer
509
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Weight at an angle
My physics knowledge is pretty basic, somebody suggested that I'll get the definitive answer of below question here.
Imagine a barbell of mass m (kg) which is ...
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1
vote
1
answer
89
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In simple terms, why does a skateboard slide in the opposite direction of its falling rider?
I would like to have a better understanding of something I’ve observed:
If I stand on a skateboard at rest, there is no movement.
If I lift my left leg, my body of course starts to fall to the left, ...
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1
vote
2
answers
95
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How do Parabolic Flights exactly work?
I understand how one can feel weightless in an elevator - in the person's reference frame, they are not being pushed up by the floor.
However, I don't understand how this can occur in parabolic flight....
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0
votes
1
answer
45
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Gravity in stationary space
Since 95% of the Earth's gravity remains even at an altitude of 100 miles from the surface, a spacecraft in orbit maintains balance between Earth's gravity & centrifugal force. While in orbit, ...
- 186
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votes
3
answers
638
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Apparent weight due to the rotation of earth
My concern here is that, if you were to calculate the apparent weight of an object due to earth's rotation at the equator, most text books use centripetal force and it works totally fine, but when it ...
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4
votes
4
answers
191
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What is the microsopic reason why hot air rise? [duplicate]
The common explanation for why hot air rises is a macroscopic one. That is that the hot air is higher pressure, lower density, and therefore gravity affects it differently than the surrounding cold ...
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2
votes
1
answer
130
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How is the weight of a hanging block communicated to a scale?
I read in a physics text (Tipler, Physics for Scientists and Engineers, 5th ed.) that if we have a scale, and on the scale is a hollow box of mass $M$, and inside the box is a block of mass m hanging ...
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votes
2
answers
494
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Are we feeling 1g or 2g?
I know the acceleration by gravity is 1g, but what about the force of the floor exerting on us? is like if we replace the floor with a propulsed object going at 1g, Wouldn't the 1g of the floor or ...
user323174
1
vote
1
answer
43
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What is opposite to $\mathbf{w}_\parallel$ in a FBD of a box on a ramp?
I tried doing research on this but to no avail so my question is this:
If the normal force of an object with mass $m$ on a ramp inclined with angle $0<\theta<90^\circ$ is equal and opposite to ...
0
votes
1
answer
54
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Question about applying Maxwell's Equations to analyze a copper shaft and magnetic bearing
fellow physics people I have a question regarding the mathematics behind how a magnet will slow down as it falls through a copper pipe. I am aware of the mechanism in which this works, the falling ...
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2
votes
1
answer
2k
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What happens to a person in an elevator with a downward acceleration greater than $g$?
So I've been learning about the apparent weight of a person in an elevator accelerating upwards or downwards. I learnt that:
If it accelerates upwards with an acceleration a, Apparent weight = m (g+a)...
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2
answers
124
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If a box is at rest on an inclined plane, as you increase $\theta$, $F_n$ decreases but $F_f$ increases? [closed]
If $F_f =\mu× F_n$, then why does $F_f$ increase when $F_n$ decreases?
[Here $F_f$ is frictional force, $F_n$ is normal force and $\mu$ is coefficient of friction]
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votes
1
answer
154
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Accelerating downwards faster than gravity
What would happen if you were in an elevator that was falling downwards with a acceleration and a>g? I found an answer on this site that said that you'd hit the ceiling of the elevator. I ...
- 801
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2
answers
91
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Where do we use the maximum? [closed]
In the above problem,we have been asked to find the maximum value of $\frac{M}{m}$. But the solution the book ended up giving is the normal balancing of forces in free body diagram and came up with ...
- 1,179
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3
answers
85
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What happens to the reaction pair? [duplicate]
We know that normal force and gravitational force are not action-reaction pairs but what happens of the reaction force of normal force and $mg$ of Earth?
0
votes
1
answer
510
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If every force has an equal and opposite reaction and gravity pulls you down, where is the opposite reaction to gravity? [duplicate]
If every force has an equal and opposite reaction and gravity pulls you down, where is the opposite reaction to gravity? how come the earth doesn't turn inside-out?
1
vote
2
answers
101
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Stationary on a geodesic
If the Earth were not spinning or orbiting the Sun would we still feel gravity?
I ask because it seems to me that in that case we would not be accelerating and we would still be standing on a geodesic ...
0
votes
2
answers
217
views
Do we ignore weight of the rod in vertical spring-block system?
Problem: The first spring is placed at the
middle of the rod and the second one at the end as shown in the figure. If the end of the rod is slightly pulled up and released,
determine the angular ...
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13
votes
4
answers
6k
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Why do we feel weightlessness in water but not on land?
When we draw a Newtonian free body diagram of a man standing still on land, we draw force g and the reaction force. In water when floating still, we still have force g but we also have the reaction ...
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votes
6
answers
129
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Cancellation of forces in feeling weight
If we are on the ground, Earth's center attracts us by $mg$ force and the ground also exerts $mg$ force in the upward direction. Those two forces cancel out. So there is no net force acting on us now. ...
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3
answers
165
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Problem with Action-Reaction pairs and gravity [duplicate]
There are lot of question on this site similar to this, but they give contradicting opinions.
When standing on earth, my gravitational pull to the earth and earth's gravitational pull towards me ...
2
votes
3
answers
198
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Problem with gravity
Sorry if this question is dumb, but I don't seem to have a grasp on it.
Suppose you are on a rock in space, with no external forces acting. The rock attracts you with a force given by
$$F=G\frac{...
0
votes
3
answers
631
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Why is the normal force and the tension force greater than the weight in these examples? [closed]
A pendulum is suspended form the roof of an accelerating train. If it stays in equilibrium with respect to the train then an observer at rest will find the bob accelerating with the train. He will ...
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votes
3
answers
3k
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What is the force pair for the normal force? Clarification on Newton's 3rd Law
In the process of trying to wrap my head around Newton's 3rd law I've come across 2 definitive statements.
Forces must occur in pairs
Forces must act on different bodies
This is confusing to me when ...
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votes
2
answers
56
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Why does $g$ become 0 for this question?
A body went up for $4 \;s$ in air and then down for $4 \;s$ with the total journey of $8\;s$. Now, the graph above is a $a-t$ graph for the statement.
My question is that why does $g = 0$ when the ...
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1
answer
325
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Analyzing pulleys via Newton's Laws of Motion
If we consider a simple case like the following we can write the acceleration of the block as
$(m2-m1)g/(m1+m2)$ considering that $m2$ is heavier than $m1$
It is possible if the pulley is ...
1
vote
3
answers
228
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Tension and force equilibrium analyzed via Newton's laws of motion
I was recently solving my workheets to apply basic concepts of Newtonian mechanics. I came came across the following problem.
The above is under equilibrium. The solution the book gave me was as ...
-1
votes
3
answers
609
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Force of Gravity and $F=ma$
Imagine a box on a table. It should have $F_g$ downward and $F_N$ upward.
(I do get that we have to add those forces.)
However $F=ma$ and the box's mass is constant.
How is $F_g=mg$ if the box's ...
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1
vote
3
answers
3k
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Relationship between gravity and density
So I have recently found that flat earthers believe gravity is not real and everything goes down because of densities, obviously, if this were true things would float up as our air is not very dense, ...
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