Questions tagged [forces]

This tag is for the classical concept of forces, i.e. the quantities causing an acceleration of a body. It expands to the strong/electroweak force only insofar as they act comparable to ‘classical’ forces. Use [tag:particle-physics] for decay channels due to forces and [tag:newtonian-mechanics] or one of the other subtopics of [tag:classical-mechanics] for the dynamics of classical systems.

Filter by
Sorted by
Tagged with
0
votes
2answers
24 views

Is it centripetal force or tension force?

I'm currently learning about centripetal force, and I was shown a scenario where a man was spinning a rope attached to a ball over his head. There's a centripetal acceleration toward the center, and ...
0
votes
0answers
21 views

Finding potential given a force [on hold]

The question is you have a force given by the expression $ \mathbf F=-K(y\hat i+x\hat j)$, find the the work done in moving a particle from origin $(0,0)$ to $(a,0)$ to $(a,a)$. I tried finding the ...
0
votes
3answers
46 views

Newton's law of motion for extended objects

I read somewhere that Newton's laws may be used even if the object under consideration is an extended body, provided each part of this body has same acceleration. Does that mean that if i have a ...
1
vote
1answer
43 views

Different forces from different inertial frames?

I've been having trouble understanding this equation here derived in the picture given below. If I change reference frames to one which is moving at a velocity u with respect to the first frame, then ...
-1
votes
0answers
67 views

Is there a flaw in Newton's first law? [on hold]

When there is no external force, the object can move in a straight line or rotate around its own center of mass in a uniform manner. When there is no external force, the object does not necessarily ...
6
votes
1answer
139 views

The physics of why 3-wheeled cars are not effective

A century ago, 3-wheeled cars were quite popular, like the Morgan below. $\hskip2in$ The sale of these cars has been banned later (until recently) in many places due to the associated safety ...
1
vote
2answers
53 views

Question related to maximum static friction and minimum $\mu_s$

I think I have the right formulas the answer the following question, but there is something conceptual that is throwing me off (see end of question). A body with mass $m$ is located on a slope with ...
2
votes
1answer
38 views

Fictitious forces in relation to normal force

I am new to Newtonian mechanics, and was wondering regarding the following: The system pictured below is moving at acceleration $a$ towards the left. The mass of the ball is $m$, and there is no ...
2
votes
4answers
29 views

Is work equal to area between graph and $x$-axis in a graph of force vs displacement?

Is this true even when displacement is not in direction of force? $$W = \int (F\cos\theta)\text dx$$ and area is $\int F \text dx$. In my book that area is given as one of the definitions ...
1
vote
1answer
48 views

Juggling a ball

I have the following exercise: Explain the progress of the force you need to juggle a $5\ \rm{kg}$ ball as a function of time. Now since the question is kind of imprecise to me, I have problems ...
0
votes
0answers
32 views

How do they equate a scalar quantity and a vector quantity? What are the factors depend on $\vec F_{R,L}$?

Link to video He said that Tension is a magnitude of the force acting from the left piece to right or force acting from the right piece to left (i.e. $|\vec{F}_{R,L}|=|\vec{F}_{R,L}|=T(p)$. So, ...
1
vote
1answer
20 views

Freefall equations and forces

Consider a scenario where a 100kg mass is hanging from a rope. It's stationary, so the force it exerts on the rope is given by $F=ma$, where $a$ is the acceleration due to gravity, which works out to ...
0
votes
1answer
38 views

Searching for name of a natural constant

Everyone has heard something like this in school: The ant is the strongest animal because relating to its own weight it can lift the heaviest weights. But as far as I know the strenght of a material ...
1
vote
1answer
21 views

Calculating force on electron

How do we calculate force on electron, knowing that it behaves both as particle and wave.
0
votes
4answers
72 views

Why is it okay to decompose forces?

I guess the title says it all, it doesn't seem intuitive that we can consider something as abstract as forces to be decomposable vectors. An example would be a mass sliding off an inclined plane, we ...
1
vote
2answers
63 views

How can I measure the strength of a wrist gripper?

I've been given a hand gripper and I want to test its strength in $kg$. Of course, I could compare it to grippers with known strengths or grip it to the maximum and apply the same force on a bathroom ...
1
vote
1answer
7 views

Rigidity or Bodies with Triangular Shapes of Faces

Originally I read an answer on Quora wherein the author showed that by using magnets he made different shapes. Squares were easily deformed, so we're other shapes with square faces such as cubes ...
1
vote
1answer
41 views

Why is the tension $\vec T$ downwards in the system?

Link to video Doubt: At pulley $A$, consider the free-body diagram. Why is the tension, $\vec{T}$, in both hands downwards? I know $\vec{T}_2$ is upwards since it is the force acting upwards in ...
2
votes
2answers
131 views

Gravity as a force [on hold]

I want to know if my reasoning is correct. If you drop an object at a height, the object accelerates downward at a constant rate due to gravity. Because we defined force as the ability to accelerate ...
2
votes
0answers
75 views
+50

Should a Bismuth coin slide slowly down a magnetic ramp?

One way to check for counterfeit silver/gold coins is to "slide" them down a ramp made of neodymium magnets. You can see an example here, or just look up "silver slide". I have seen this work for ...
0
votes
0answers
25 views

Surface tension [on hold]

A thin metal ring of internal radius 8 CM and external radius 9cm is supported horizontally from the pan of A balance so that it comes in contact with a glass vessel. It is found that ans extra weigh ...
0
votes
1answer
32 views

Can you please explain the statement in the David Morin's Classical Mechanics? [duplicate]

For example, in a hanging massless rope, or in a massless rope hanging over a frictionless pulley, the tension must be the same at all points, because otherwise there would be a net force on at ...
2
votes
2answers
45 views
+50

Why normal reaction, tension, and friction forces are reference frame independent?

I can not provide a whole manuscript of examples where I can justify that these forces are reference independent. I don't think that there is any such case where these forces are reference dependent. ...
1
vote
2answers
79 views

Chain slipping off a sphere - Mechanics problem

A uniform flexible chain of length l rests on a fixed smooth sphere of radius R such that one end A of the chain is at top of the sphere while the other end B is hanging freely. The chain is held ...
0
votes
2answers
58 views

Vertical component of friction

If we have a car of mass $m$ sliding around a banked curve of angle $\phi$ with some coefficent of friction ${\mu}$, then the normal force will be $$Ncos\phi= mg + {\mu}F_{g}\sin\phi$$ But this ...
0
votes
1answer
44 views

Unequal forces acting on two blocks connected by a string [on hold]

Two blocks A and B are separated by some distance and tied by a string as shown in the figure. Find the tension in the string. I can see that maximum value $f_1$ can attain is $7 N$ and the maximum ...
4
votes
5answers
514 views

Do objects besides strings, ropes, and rods have tension?

Why do we define tension only in strings and ropes and rods and such? Shouldn't every object experience tension force? Like when you pull a paper from opposite sides, it gets taut, and experiences ...
1
vote
1answer
31 views

Tensions in objects other than ropes

Can you have tensions in objects other than strings and rope? suppose you have a piece of paper and you pull at it from both ends it becomes sort of taut similar to how a rope does when you pull at ...
0
votes
3answers
54 views

Equilibrium of a body in torque problem

I was watching a video about torque in which the task was to find the force $F_2 $ when a body is in equilibrium. The person in the video said that in order for the body to be in equilibrium, two ...
1
vote
2answers
22 views

Is tension equal to the force a person applies horizontally to an inanimate object? [on hold]

Suppose a person is pulling on a rock, such as below: Should the tension in the string be exactly equal to the force the person applies when the whole system, (person, rope and the rock) are ...
0
votes
4answers
41 views

Will friction on tyres due to road still act if the vehicle is moving with constant velocity?

A car moves with the help of friction from ground...while analyzing a car moving with constant velocity..should one consider the frictional force acting at the contact point of road and wheel? If ...
1
vote
0answers
38 views

Friction at high speeds

I am reading a book which mentions that frictional force is not exactly proportional to the normal force at high speeds. Quoting: Once the bodies slip on each other frictional force is, $kN$. This ...
1
vote
1answer
46 views

Understanding of Gauss law using vector fields

I was going through the conventions and terminologies followed to describe the magnetic interactions. I understood that the field lines are just a simpler representation of the magnetic interaction ...
0
votes
0answers
20 views

Forces/momentum/impulse repartition and balancing over several rigid bodies touching each other

I've got a problem about physics modeling in a really particular case. I'm not exactly sure if i have to ask it into physics or gamedev,but i suppose the problem is best suited here, since it is about ...
0
votes
0answers
34 views

Validity of Newton's second law in a non-inertial reference frame

Suppose two observers are mutually interact through gravitational force (assuming they are alone at space). If the reference frame is fixed in one of the observers could the observer in the reference ...
1
vote
0answers
35 views

Confused about summing over the velocity squared term

Consider a cubical box, L on each side. The box contains N molecules of ideal gas, each of mass m. All collisions are elastic. The force exerted by one molecule when it collides with a wall of ...
1
vote
0answers
30 views

How much energy does it require to fuse a proton with a nucleus? [closed]

If calcium 45 is bombarded with protons and one proton is to be added to the nucleus of the atom, how much energy is required to overcome the electromagnetic force?
0
votes
1answer
55 views

Is it possible to find $\mathbf{v}$ explicitly when $\mathbf{F}$ varies with $\mathbf{v}$?

I have the following problem (NO, this is not to ask for a solution to this problem). A block is placed on a plane inclined at an angle $\theta$. The coefficient of friction between the block and ...
0
votes
2answers
74 views

Understanding Hooke's law

This is taken from "Physics a general course, volume I" by I.V.Savelyev. How is it that "Any part of the spring acts on another part..."? I understand that at each "point" we can assign $F_{el}$, but ...
1
vote
0answers
34 views

Collision of particles [closed]

I read in a book that in both elastic and inelastic collision, the interacting forces after the collision become effecitively zero, the potential energy of the system remains the same both before and ...
0
votes
1answer
33 views

Measuring Tensile Strength in an alternative way

TL;DR: I make a cylindrical disc out of material X. Fill it with fluid and apply pressure on top of the disc which pushes the curved part of the cylinder outwards till fluid pressure breaks it. ...
6
votes
1answer
623 views

Confused about the differential of a quantity

We know that by definition, the differential of a single variable function $f(x)$ is $$df(x)=\frac{df}{dx}dx$$ analogously, for a multi-variable function $f(x,y,z)$ $$df(x,y,z)=\frac{\partial f}{\...
0
votes
1answer
50 views

Tension in a string with unequal forces

Let's suppose that there is a massless string. If we apply unequal forces along the rope along a straight line, let's say we apply 60N and 70N forces, then what is the tension in the rope? It would ...
2
votes
0answers
31 views

Is the force due to mass flow proportional to the square of the mass velocity?

I'm trying to calculate the force on a surface due to some flow of water against that surface- for simplicity, assume that the mass flow vector is orthogonal to the surface. Using dimensional ...
0
votes
3answers
78 views

Why bodies with different masses reach gound at the same time in vacuum? [duplicate]

According to Newton's Gravitation Equation $$F=G \dfrac{M\cdot m}{r^2}$$ force of gravity depends upon mass of both objects, and $$F=ma$$ means force is proportional to acceleration. Then why do ...
-1
votes
3answers
115 views

The fastest man on Earth physics

The legs of the world's fastest man (Usain Bolt) can develop up to 5 times the force compared to those of normal people. What stops him from being faster? A normal healthy high-school student can ...
3
votes
1answer
53 views

What is the Magnus Coefficient for a Golf Ball?

When researching the magnus force I have often come across this formula to calculate it: $$ F=S(\vec{\omega} \times \vec{v})$$ However I have been unable to find any source giving the value of $S$. ...
0
votes
2answers
45 views

Laws of motion (friction on rough inclined plane)

For equilibrium of a body on an inclined plane of inclination 45°. The coefficient of static friction will be 1) greater than one. Why? My question is why do we use greater than sign instead of ...
-2
votes
0answers
16 views

Wouldn't the pressure on the top of the wing decrease without viscosity? [duplicate]

Someone always tells me that there is no lift without viscosity. I think without viscosity, the air pressure on the top of the wing will also decrease. As shown in the figure, without considering ...
3
votes
2answers
80 views

Velocity-Dependent Potential and Helmholtz Identities

I'm currently working through the book Heisenberg's Quantum Mechanics (Razavy, 2010), and am reading the chapter on classical mechanics. I'm interested in part of their derivative of a generalized ...