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 ...
0
votes
0answers
28 views
system of tubed colliders and desired direction of movement
Imagine tube with mass M and inside it an object with mass M2 that we can force into direction x or -x. Let us say that desired direction is x. Collision between the wall at the end of the tube and ...
-3
votes
0answers
47 views
How much force is required to lift this car (all details/info provided)? [closed]
I have the details and info, but not the knowledge on how to determine the weight in any sensical manner.
Approximately, on or off, or exact, about how much force is need to lift this car from the ...
0
votes
1answer
35 views
Question on static friction [closed]
This is the question, and the answer is given as 2).
Now my basic doubt is, are they asking us the direction of the total contact force on the object by the floor? Or, are they asking the direction ...
1
vote
1answer
53 views
Mechanics question (a block on top of a block)
This question is very similar to this one here.
A block of mass $m_1$ is placed on another block of mass $m_2$ lying on a smooth horizontal surface.
The coefficient of friction (static and ...
0
votes
1answer
39 views
In Newtonian pressure, what type of function is force?
This is pressure in Newtonian mechanics:
$$P=\frac {dF}{dA}.$$
What does this mean?
(Doesn't it mean that force is a function of area?)
What type of function is force?
6
votes
2answers
119 views
Confusion with derivation of fictitious forces
I read the mathematical derivation of fictitious forces on Wikipedia and I'm having trouble understanding it. I went on a few other sites looking for a better derivation, but they're all basically the ...
3
votes
3answers
63 views
The force arrow for centripetal force points in the opposite direction of my calculation?
I need someone to clarify a conceptual problem I can't seem to surpass. Image there is a rollercoaster loop and a rollerbcoaster car enters the loop at high speed.
Once the car completes the full ...
1
vote
0answers
43 views
Calculation of magnetic force magnitude from a parmenant magnet
I was wondering how strong a magnet should be in order to be able to horizontally attract 0.2 Kg of pure iron at a distance of 0.3 M. Since I know nothing about magnets, I started looking for ...
0
votes
1answer
129 views
Tension in a massless string around a pulley
A pulley having some mass has a massless string around it,with two unequal masses at the end of the string .Sufficient friction is present between pulley and the string such that the string does not ...
-4
votes
0answers
30 views
Is Gravity a Push force? [duplicate]
I am not a Science graduate, so may be I have an unclear concept. but one thing keeps coming to my mind so I thought to discuss here with someone interested in Gravity.
Here I go: "I feel there is NO ...
15
votes
4answers
432 views
+50
Why do whips hurt so much?
What exactly is the mechanism that makes a whip deliver such a strong impact? Elasticity, torque, or pressure? Just hitting something with a plank doesn't deal nearly as much damage. What's the ...
-3
votes
0answers
31 views
Block over block Problem [closed]
There are two blocks one over the other , both on ground , masses are 2 kg for top one and 5 kg for bottom one , coefficient of friction between both is 0.8 and between lower one and ground is 0.2 . ...
0
votes
1answer
67 views
What type of pump to lift water up 10 metres? [closed]
I've looked at the following question but I'm not sure it answers my question (end): -
Calculating the mechanical power of a water pump
by Phil Frost
I am building a Koi carp pond at the ...
0
votes
1answer
42 views
Calculate magnitude of force acting on some area by falling object
I have simple question: is it possible to calculate magnitude of force acting on some area by falling object?
Let's say I have an object with mass $5\text{ kg}$. I drop that object in height 1 ...
1
vote
1answer
111 views
Buoyancy Problem - Cubes in water
I have a tank with water (10 m high) , with an ideal seal at the bottom (water can't fall down, but can enter bodies).
I have a system of 6 cubes ( of polystyrene density= 20 Kg/m^3) with dimension ...
3
votes
1answer
106 views
Is there any potential associated with magnetism
Can anybody please tell me if magnetism is a conservative force or if there is a field associated with it? How to reason? One thing I know is that the work done by a magnetic force is $0$.
-4
votes
0answers
32 views
Basic force in gravity responsible for attracting everything including nonmetal [closed]
Why do things get attracted? It is said that there is a magnetic field around the earth, but how can the attraction of non-metals be explained in terms of magnetic fields?
How can one generate this ...
2
votes
1answer
103 views
Is any work done when I walk?
I am trying to figure out the amount of work done when I walk X miles or for X minutes. So I got Work=Force x Distance and Force=Mass x Acceleration and Acceleration=(change in velocity)/time. I am ...
-4
votes
3answers
80 views
Safest place to sit in the car [closed]
I have to sit in a car which has normal seats in the front, and lounge type chairs at the back, with seatbelts only in the front. The driver drives fast, and I think I may have an accident. So, ...
-4
votes
0answers
29 views
Find amount of force to move a 18 kg mass 0.1 seconds [closed]
Force is coming from two pistons pushing at 45 degrees applied to two adjacent corners of a square (0.6 m x 0.6 m) rigid plane. Mass of the plane is 18 kg. Piston stroke is 20 cm, piston bore is 40 ...
5
votes
1answer
150 views
Magnetic force doesn't do work and therefore can't change the KE of a particle?
I am having a real hard time understanding the principles behind a question I've come across during test prep. Here is the question:
Q: A proton and an electron are traveling in the uniform ...
2
votes
1answer
71 views
Understanding Kepler's problem
I wanted to know a few things about elliptical motion, that I do not understand so far.
Let's imagine that we have an attractive gravitational two body problem where both bodies carry out elliptical ...
-1
votes
3answers
154 views
How much torque does it take to turn a doorknob? [closed]
How much torque does it take to turn a doorknob? I'm not looking for an exact answer, just a ballpark for someone who doesn't have a sense of everyday amounts of torque.
Here's a very ordinary ...
1
vote
2answers
67 views
force applied not on the center of mass
when applying a force not on the center of mass of the body, the body will get both linear and angular mumentom (right?).
does the linear velocety from this force (that is applied not on the center of ...
1
vote
4answers
63 views
Action Reaction when I pushing a trolley?
I tried to explain how those force work but I can hardly figure it out.
I exerted a force on the trolley and there will be a force on trolley on me as well. This is the newton's third law. But why the ...
1
vote
1answer
43 views
Universe with ZERO Fundamental Forces
Warning: I am not a physicist so please excuse my naivety!
As you all know, physicists think that there exist four fundamental forces.
Would a universe with zero fundamental forces be possible, at ...
2
votes
2answers
77 views
Sum of all forces
Let us glue up these two images, where we get closed loop thrust of water. Force $F_3$ has direction $-x$ and force $F_2$ has $x$ direction. What is the sum of all forces? Can it be more than zero? ...
1
vote
1answer
69 views
A block, a string and Newton's third law
So this is a general force diagram of the system shown. My question is, according to the third law, if the block is exerting a force of magnitude mg on the thread in the down direction, then the ...
0
votes
1answer
38 views
Equilibrium and Torque [closed]
How does one calculate the forces that exert on a wooden board held by two trestles if one knows the weight of the board as well as the distance of both trestles?
2
votes
1answer
47 views
Summing moments, where have I gone wrong?
Because I don't have enough rep to post images, the question is question 3 part iii) from here: http://www.mei.org.uk/files/papers/m209ju_jk32.pdf
The surface at the contact point B is rough. The ...
0
votes
4answers
79 views
How can acceleration $a$ be zero when applied force $F$ is non-zero?
An object is at rest and stays at rest, but an attached rope pulls with increasing force. What is the acceleration?
The correct solution is that acceleration is constant and 0. Obviously $a= dv/dt ...
-1
votes
1answer
52 views
What is the minimum wrap around angles of belt, timing belt and chain? [closed]
I read a website which said the minimum wrap around angle for belt on pulley is 120 degrees, However, it doesn't say whether it is belt or timing belt. Also I want to find the minimum wrap around ...
-2
votes
1answer
61 views
Question on friction [closed]
Please look at the figure carefully. The question is written, and one has to match the two columns 1 and 2 given under "choices and explanation". Please tell me if I am really wrong, i.e. would you ...
0
votes
0answers
24 views
Force being applied to an object [closed]
I am working on a project and I do not have a clue about Physics. I have a 3400lb,1542kg object traveling at 210mph. When it is stopped by another object that is not in motion, what is the force of ...
8
votes
3answers
209 views
Where does the extra equation come from to determine the forces from an object on a table?
I have a question about basic statics but somehow I cannot manage to find the answer on my own (btw, this is not a homework. It's been so many years since school for me...).
The problem is very ...
1
vote
1answer
67 views
Inclined plane question
An object, mass $m$ is placed on an incline, angle $\theta$. System is at equilibrium. coefficients of static and kinetic frictions are $\mu_s$ and $\mu_k$ respectively. Then:
1) What is the Total ...
3
votes
1answer
71 views
Why does this screwdriver roll in a curved trajectory?
I am trying my level best to give this screwdriver a horizontal push only, but it is going in a circular path. I thought of uneven friction due to non-uniform normal reaction...what do you think? I ...
2
votes
1answer
28 views
Magnetic Force on a Loop and number of turns
Suppose we have a rectangular current-carrying loop with current $i$, then we know that the magnetic force on each side can be found as:
$$F=iL\times B$$
Where $L$ is the vector in the direction of ...
0
votes
0answers
47 views
electrostatic repulsion [closed]
Consider a homogeneous ring of radius $R$ made of a thin wire of cross section $A$ with $R^2≫A$. A charge $Q_1=10\mu C$, uniformly distributed over the ring, broke it apart due to electrostatic ...
-2
votes
1answer
56 views
A double-sided lever and multiple forces [closed]
Assume a double-sided lever where the left arm has a length of a and the right arm has a length of b + c. Please refer to this ...
0
votes
1answer
27 views
Kinetic energy when $F(t)$ graph is given
The very basic problem here is that the point where this graph ends is ambiguous. I mean, what is the corresponding $y$-value for the point whose $x$-valu is $4.5s$? Then I think we should find the ...
2
votes
2answers
72 views
Intuition contradicting answer for calculating pressure
I have a cylindrical container say of some base area $A$. The atmospheric pressure is $P_0$. The cylinder is moved at an acceleration $a$ horizontally right. I need to find which base would have to ...
1
vote
2answers
64 views
Momentum, Impulse and Newton's Second Law of Motion
Newton formulated his Second Law as such:
$$\sum{\vec{F}} = \frac{\delta \vec{p}}{\delta t}$$
and of course, $\vec{p} = m \vec{v}$.
Why is it that if the net force $\sum \vec{F}$ is constant (which ...
5
votes
2answers
92 views
How can a car's engine move the car?
Newton's First Law of Motion states that an object at rest or uniform motion tends to stay in that state of motion unless an unbalanced, external force acts on it.
Say if I were in a car and I push ...
-1
votes
1answer
41 views
If An Object Explodes With A Force, What Force Are Fragments Given?
So let's say for example I have an object with 5kg of mass.
It explodes with a force of 500N.
The object fragments into four fragments: a 0.5kg, a 1kg, a 1.5kg and a 2kg object.
What force does ...
0
votes
1answer
50 views
Another Inclined plane question
I did the FBD, and I found too many variables which are not eliminating...Moreover, I believe this question is based on kinetic and static friction. But, $\mu$ here is ambiguously defined...How Do I ...
-1
votes
1answer
65 views
Comparing Static Frictions
In this figure, which of the static frictional forces will be more?
My aim isn't to solve this particular problem but to learn how is static friction distributed . Since each of the rough-surfaces ...
0
votes
2answers
78 views
Massless string Paradox
If we introduce the notion of a massless string to denote the fact that net force on a massless string will always be $0$, since it is massless . How can these massless strings ever accelerate when ...
1
vote
1answer
56 views
How large of a solar sail would be needed to travel to mars in under a year?
I'm attempting to approach this using the identity
$$F/A = I/c$$
I can solve for Area easily enough
$$A = F(c/I)$$
and I know the distance $d$ is
$$d=1/2(at^2)$$
But I'm having difficulty trying to ...
2
votes
1answer
34 views
Falling through the ground [duplicate]
I do not know much about physics but I know that according to Newtons third law of motion when we walk we are pushing the ground down but the ground is pushing us up. What force is making the ground ...
