Questions tagged [free-body-diagram]
A pictorial device which analyzes forces present on any body with the use of vectors. Allows easier grasping of problems involving either objects at equilibrium or in motion. Can be used to predict presence of forces.
1,618
questions
0
votes
0
answers
16
views
Apparent weight of body due to rotation of earth [duplicate]
This question has been asked several times on this site. However, most of the answers were
qualitative in nature.
Suppose a body is placed at a point on earth's surface at latitude $\theta$ from the ...
- 332
1
vote
0
answers
27
views
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 ...
- 49
2
votes
0
answers
48
views
Acceleration of masses connected by a leaning pole [closed]
I'm looking at the following mechanical system, originally described in an exercise from Kleppner and Kolenkow (Problem 2.7, 2nd ed):
A pole of negligible mass leans against a wall, at angle $\theta$ ...
- 173
1
vote
3
answers
53
views
Is it possible for friction to be the sole provider of centripetal force?
Imagine a rough turn table with a wooden block (let it have negligible dimensions for the sake of simplicity) on it. The turn table is perfectly horizontal and is rotating with a constant angular ...
- 1,101
0
votes
1
answer
19
views
Tension In Belts when pulley is accelerating [closed]
If the driving pulley in a belt drive system is accelerating will the tension forces still be equal and opposite in both sides? That is will F2 still = F2 in loose lever side,and F1=F1 in taut lever ...
- 83
0
votes
1
answer
31
views
Been confused about string constrained motion for a while
Let's have a look at the following set up:
Suppose Block C is moving downwards with a velocity "u" and we are required to find the velocity of bead "v" . So what we were taught in ...
1
vote
1
answer
66
views
$F=\frac{dp}{dt}$ for falling chain [closed]
There are several questions on Physics SE regarding the problem of a falling chain. However, to the best of my knowledge, no one has yet asked the following one. Consider the scenario presented in ...
- 1,494
0
votes
1
answer
36
views
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, ...
- 2,955
0
votes
1
answer
31
views
Conservation of energy when a block ascends a curved wedge [closed]
With reference to the above diagram:
When the block ascends on the wedge, wedge also starts moving in forward direction due to the normal force (horizontal component) applied by the block. Block keeps ...
- 441
1
vote
3
answers
55
views
Reading of weighing machine [closed]
Consider the following situation:
The following ball is released and just after that reading of weighing machine is noted.
Now, it is given that Mass of container is $M$ and mass of liquid is $m$ and ...
- 265
2
votes
2
answers
74
views
If the mass of a body suddenly decreases, would it jump due to normal reaction?
Suppose the body of mass M is on a frictionless table, assume g to be the gravitational acceleration. Assume mass of the body changes suddenly(by m)
I was thinking since the mass changes suddenly, the ...
6
votes
3
answers
295
views
Pressure on nail and tip of nail hammered into a wooden board
While studying Pressure, I came across such a question:
A nail is driven into a wooden board by using a hammer. The impact of the hammer on the head of the nail produces a thrust of 25 N. If the area ...
- 444
0
votes
5
answers
98
views
How is it possible to drive a nail into a piece of wood using a hammer? [duplicate]
I understand that the hammer applies a force on the nail (of magnitude say, 25 N). The force is then transmitted through the nail onto the wood and thus, the nail exerts a force of 25 N on the wood.
...
- 444
0
votes
5
answers
105
views
Why is centripetal force acting 'away' from centre in this situation?
In this problem, a guy is moving along this circular track at constant speed.
When he is at B, the centre of motion is 'downwards', isn't it?
So there must be centripetal force on the cyclist that is ...
- 438
1
vote
1
answer
23
views
Why do we use sum of radial forces in pendulums? [closed]
The problem is: A small rock with mass m is fastened to a massless string with length L
to form a pendulum. The pendulum is swinging so as to make a maximum angle of theta with the vertical. Air ...
1
vote
3
answers
82
views
Why can't I use $\tan()$ to find the force of tension within a rope that forms a triangle? [closed]
Apologies if this is too simple, but my teachers could not give me an answer. The following is a question from my grade 12 physics homework:
Now, the solution for $T_2$ is simple:
$T_{1_x} =T_{2_x}$
$...
- 13
0
votes
3
answers
83
views
Misunderstanding on Newton's Third Law [duplicate]
I am confused on how objects are able to move, even though Newton's third law states that every action has an equal and opposite reaction.
I feel it would be easier to explain my misunderstanding in ...
- 171
0
votes
4
answers
51
views
Equilibrium on a plank
Consider the classic scenario of an equilibrium with a man standing at the centre of the plank, with the plank being held up by two trestles, say the man exerts a force of 500N at the point he is ...
- 157
0
votes
1
answer
29
views
Free body diagram of mass-spring system #2
I've attempted to draw a free body diagram of the forces acting on the mass again, but I'm confused about the directions. In many of the sources that I've read, they say that the Fres = Fs + F. Fs is ...
- 61
0
votes
2
answers
78
views
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 ...
- 131
0
votes
1
answer
28
views
Friction when a body is moving underneath another
I feel it would be better to explain my question through an example:
When I push a table (and it moves), with a mass atop of it, how does the mass stay on the table, as there is no direct horizontal ...
- 171
7
votes
6
answers
2k
views
Would objects float when completely submerged in an incompressible liquid?
Assuming that the liquid is at the same temperature throughout, I presume that a compressible liquid causes flotation because there are more molecules striking the underside of the object than the top....
- 2,955
5
votes
1
answer
876
views
If fluids exert force in all directions then why do objects float? [duplicate]
My question is that when we place a body in water it exerts a buoyant force but it exerts an equal force in downward direction then why its buoyant force is greater and the object floats?
- 67
0
votes
1
answer
27
views
A block staying at rest in a two-block system
Let us assume a scenario where two blocks are connected by a spring and are at rest in a frictionless surface. If we give a velocity $v$ to one of the blocks, it will try to compress the spring. Then ...
- 945
0
votes
2
answers
44
views
A question involving a system of pulleys [closed]
The problem
I recently was trying to solve a problem (1) from David Morin's 'Classical Mechanics'(2). Before going ahead and solving the full problem, I tried solving a simpler version of it:
In the ...
1
vote
3
answers
87
views
Why are these two tension forces equal? [duplicate]
I am new to this topic and my teacher told me that these two forces in the cable will be equal. I would like to know why this is case.
- 57
0
votes
1
answer
26
views
Would a circular shape disk of radius $R$ and mass $M$ roll on ice (no friction) due to a Rope attached to the top that pulls the disk horizontally?
Normally for example in an inclined plane we have a circular disk that rolls down if the surface of the incline is rough (friction is present), this creates a torque that causes the ball to start ...
- 45
1
vote
1
answer
34
views
Critical force for a system comprised of a compressible and incompressible parts
What is the critical buckling force needed to be applied on a system of made out of two parts?
The parts of the system are as depicted in the picture:
incompressible elastic beam - on top
...
- 115
3
votes
2
answers
154
views
Follow up question on a block on an accelerating inclined plane
A follow-up on this post: How can an accelerating inclined plane prevent a block on it from sliding?
Farcher's answer states that
"If F is larger than in the no relative movement condition then ...
1
vote
0
answers
33
views
Does normal force always point perpendicular to the surface? [closed]
I drew arrow #2 on an AP Physics C assignment, but my teacher said it was wrong and took away a point since it was not perfectly vertical. I feel like it could be arrow #2 though with the information ...
- 11
1
vote
1
answer
48
views
Velocity and Acceleration in an Accelerated Atwood Machine
Suppose an ideal Atwood machine is pulled by a constant force $F$ against gravity. I am unable to understand the dynamics of the system. Do the blocks move in such a way that the "increase" ...
1
vote
2
answers
57
views
The net force received by the bus handle during the acceleration of the bus
Re-post the question by complementing the inaccurate information.
First, I'm just an ordinary person who's interested in physical phenomena and physics. I apologize for not expressing it through ...
- 65
1
vote
2
answers
60
views
Confusion about tensions and friction in pulley problem
The pulley is not massless, and has moment of inertia about the hinge point $I$. We assume there is no slipping of the rope. My teacher said that the first equation we make will be $T_1 = f + T_2$ or $...
- 278
5
votes
5
answers
194
views
Why don't weighing machines show the weight of the atmosphere?
The school experiment of hanging two balloons, one filled with air, other empty, on a ruler, show that air has weight.
A person has weight. It's shown on a weighing machine. A pencil has weight. It's ...
- 159
1
vote
1
answer
32
views
Tension Force of Someone Passively Leaning Against a Rope [closed]
Suppose I have a rope, and my weight is $W$. If I tie the rope to a tree and hang from it, I will apply a tension force of $W$.
But suppose that I don't have a tree, and yet I want to generate a force ...
- 113
2
votes
1
answer
54
views
Mechanics of book falling on it's side [closed]
I have the following question that I'm struggling with.
Imagine you have a very thin book (we consider it's thickness to be 0) that sits upright. At some point the book falls to it's side. How can we ...
- 23
1
vote
0
answers
20
views
I need help figuring out the direction of reaction forces between the two blocks and drawing the FBD [closed]
The problem is as follows -
Two blocks A and B each of mass $m$ are placed on a smooth horizontal surface. Two horizontal forces $F$ and $2F$ are applied on both the blocks $A$ and $B$ respectively. ...
- 85
37
votes
7
answers
6k
views
Can spinning arms really help you balance on the edge of a cliff?
This is how many cartoons depict a character about to fall from the edge of a cliff. You can see movie characters do it. You can also see real people doing it. But does spinning arms like that ...
- 8,455
7
votes
4
answers
888
views
Does an open or a closed cage of canaries weigh less when they are in flight? [duplicate]
Okay this is a bit of an old classic, but I don't think I've heard a good reasonable explanation for what happens:
If you put a cage of canaries on a weigh scale and they take off does the scale still ...
- 714
3
votes
2
answers
160
views
Why do levers work?
If we have 3m beam with a fulcrum 1m from one end, we will find a balance by having a 1kg weight on the long end of the beam and a 2kg weight on the short end.
Similarly, I will need much less ...
- 143
0
votes
0
answers
33
views
Does an object submerged in water affect the total weight of the water tub, if the displaced water is spilled out?
Suppose you have a tub filled to the brim with water and it rests on a scale so you can measure the weight. Any displaced water is spilled out of the tub and so no longer contributes to the weight ...
0
votes
3
answers
71
views
Why is an object considered less buoyant if it is fully submerged? [closed]
I found the following on BYJUS:
A body experiences greater buoyant force when it is fully submerged compared to when it is partially.
https://byjus.com/question-answer/a-body-experiences-greater-...
- 11
0
votes
0
answers
28
views
Buoyancy force | What is the correct way to describe and explain Buoyancy force at a macroscopic but also a microscopic perspective
Have you ever noticed objects going down in a pool, reaching equilibrium? Often, when a submerged object (and in contact to the floor) is moved, it start going up again. Why?
This kind of scenarios ...
- 244
1
vote
2
answers
82
views
Can I weight a weighing machine by putting it upside down?
For the sake of this question let us assume a flatbed scale where I can put the mass on top in order to measure on a flat surface which forms the top of the scale:
Will it give correct reading if I ...
- 468
-1
votes
1
answer
34
views
What forces act on the block? [closed]
I can not understand why the forces N1 and N2 act on the block. What are these forces and why did they appear?
0
votes
1
answer
69
views
What is point of application of force? [closed]
My textbook said that point of application is the exact location at which a force is applied to a body. But I know that there are some forces that their points of application outside the body (like ...
- 151
0
votes
2
answers
62
views
How To Find Direction of Normal Contact Force?
I am a little bit confused. while doing questions I can see direction of normal forces are different. In Some Cases, It is perpendicular to the contact surface and towards the object on which normal ...
0
votes
3
answers
36
views
Archimedes principle implication
I need a clarification of one of the consequences of archimede's principle. My main doubt is why is it that the pressure on a certain object is independent of that object? This makes total sense, just ...
7
votes
2
answers
754
views
Why do we always assume in problems that if things are initially in contact with each other then they would be like that always?
I am a high school student and I am confused in one thing:"Why do we always assume in problems that if things are initially in contact with each other then they would be like that always?"
1)...
- 432
1
vote
2
answers
75
views
How can we jump when the ground does no work on us? [duplicate]
This may seem like a silly question, but how can we jump when the ground does no work on us?
When we jump off the ground, the ground does not move. This means the force from the ground on us does zero ...
- 49