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 ...
-2
votes
1answer
142 views
Newton first law of motion, braking suddenly in car
While driving down the road, if you hit the brakes suddenly, your body moves forward. Explain the reason for this.
1
vote
0answers
41 views
Truck driven from a small motor that can carry a heavy load, yet can travel fast.
I am building a truck from trash as materials. I have one small motor and a a few small gears, but no other engineered materials are allowed. The truck must carry a load for a distance of 3m. The ...
0
votes
1answer
71 views
What is the significance of Planck force?
I have been curious to find what could be the significance of Planck force? It is calculated by the formula $c^4/G$,
where $c$ is the speed of light; $G$ is the gravitational constant. Thus (the speed ...
1
vote
2answers
106 views
Additional mass of block on inclined plane
I would like some help in solving this problem.
Height is 15 cm , base is 88 cm
My attempt:
$$(119.3 + m)(\sin(\theta)) = (88*9.8)$$
$$ 15^2 + 88^2 = 89.269^2 $$
$$ \sin^{-1} = 15/89.269 $$
$$ ...
5
votes
3answers
346 views
Particle coming across a step potential barrier
My quantum mechanics textbook says that when a particle (in the classical case) comes across a potential-step barrier of finite height, if it has sufficient energy to surmount the barrier, it will ...
1
vote
2answers
113 views
Will a rotating object traveling along a linear path continue to rotate forever in space?
Suppose engineers built a cylinder-shaped space ship which rotates to create artificial gravity:
...
0
votes
0answers
41 views
Help with forces [closed]
The 72.0 kg climber in the figure is supported in the "chimney" by the friction forces exerted on his shoes and back. The static coefficients of friction between his shoes and the wall, and between ...
1
vote
1answer
161 views
Force exerted on a cone
This is probably a pretty elemental question, but I can't figure out what the concept is called or how to calculate it. Say you have a solid cone shaped piece of ice, you hold it in your hand and ...
0
votes
0answers
66 views
On a Pilates reformer, how much resistance is from springs and how much from weight of user?
Here's picture of a Pilates Reformer machine: image
How much of the force required to move the carriage is based on the resistance of the springs, and how much is based on the weight of the user? ...
4
votes
3answers
398 views
A fly in an accelerating car
A fly is flying around in a car, the fly never touches any surface in the car only fly’s around in the air inside the car. The car accelerates. does the fly slam in to the rear window. or does the fly ...
1
vote
1answer
61 views
Charged plane in an electric field acceleration
A perpendicular plane to an electric field's lines of force has more electric flux than a plane that is in parallel with the lines of force, right?
Does this mean that a charged plate would ...
5
votes
2answers
160 views
Relativistic equivalent of a spring-force?
Usually what helps me understand a concept better in physics is to write a simulation of it. I've got to the point where I'm competent in the basics of special relativity, but, I can't figure out how ...
0
votes
1answer
266 views
Block Hanging From a Rope [closed]
A block of weight 47.0 N is hanging from a rope. The tension from the rope is pulling upward on the block. The block is accelerating downward at a rate of 1.53 m/s2. What is the magnitude of the ...
-1
votes
2answers
163 views
A simple logical problem regarding pressure and force
Suppose a 2 meter long pipe, with area of cross section is $1 m^2$. The pipe is vertically placed, with the bottom end closed. Inside the pipe, at the closed bottom end, there is $1 m^3$ of air, ...
2
votes
0answers
49 views
Semiflexible discrete polymer chain
Suppose we have a 2D polymer model described by a set of 2D vectors {$\mathbf{t}_i$} ($i=1,2,\dots N$) of length $a$.
The energy of the polymer is given by:
$$
...
1
vote
0answers
63 views
How can I calculate all of the tensions in the cords? [closed]
I have been stuck on this problem for the last half, and to be honest I don't even no where to begin. I'm being asked to calculate all of tensions for the cords. I know I'm supposed to use $\cos$ to ...
2
votes
3answers
158 views
In projectile motion, what does it mean for the motion along the $x$ and $y$ axis to be independent?
In projectile motion, what does it mean for the motion along the $x$ and $y$ axis to be independent?
This question is referring to the concept of projectile motions.
2
votes
5answers
177 views
Forces acting on a point mass in a spinning rigid body
I have learned that all spinning objects will continue spinning even if no force is acting on it, and the tendency to do so is called moment of inertia. But I wonder about the fact that a single point ...
0
votes
0answers
52 views
An ideal toilet roll on a flat surface [closed]
Suppose we have an ideal toilet roll on a flat surface with the outer end of the roll fixed to the surface. After we give the roll an initial velocity such that the roll unwinds, what happens to the ...
1
vote
0answers
92 views
How much force is required to hold an umbrella?
Assuming a small umbrella (e.g. http://www.amazon.com/ShedRain-WindPro-Umbrella-Close-Size/dp/B001DL5WN0). What are the factors that need to be considered? I assume where I hold the umbrella might ...
2
votes
2answers
137 views
Contact force betweeen 2 objects
Suppose that we have 2 objects next to each other.The object at the left is A and the object at right is B.now we have these situations:
1) we push B to the left.
2) we pull A to the left.(in this ...
1
vote
1answer
173 views
Work done in projectile motion
A projectile is shot at some inclination to the ground. It falls at another point having R distance from the initial point on the ground. Is there any work done?
If initial velocity vector is $(u\cos ...
1
vote
0answers
36 views
stopping distance [closed]
if it takes a 4 door sedan x amount of feet to go from 65 mph to 45 mph (and i don't know how many feet that is) on a dry straight road,
how many feet would it take for a large Mack truck ...
3
votes
1answer
66 views
Relation between Casimir and hydrophobic effects
Background
Some years ago I was studying "Fundamentos de biología" (Biology fundamentals) and learned how the lipids create a bilayer due to the water repulsion. Some time later I learned that this ...
1
vote
2answers
161 views
Is there any case in physics where the equations of motion depend on high time derivatives of the position?
For example if the force on a particle is of the form $ \mathbf F = \mathbf F(\mathbf r, \dot{\mathbf r}, \ddot{\mathbf r}, \dddot{\mathbf r}) $, then the equation of motion would be a third order ...
3
votes
1answer
166 views
Is there any case in classical mechanics where Newton's (strong) third law doesn't hold?
Is there any case in classical (non relativistic) mechanics where the strong form of Newton's third law does not hold (that is, reaction forces are not collinear)? For example, if we consider a system ...
4
votes
3answers
185 views
How can a vertical force cause motion at an angle?
I just started learning physics 3 days ago and am having trouble understanding what I am doing wrong. Can someone please explain my error(s)? Thanks!
We have a 1kg object on a plane at a 30 degree ...
0
votes
0answers
220 views
How to calculate the force between two different magnets?
I'm doing an experiment and I need to calculate the force between two magnets with different stats, different sizes and flux density.
I learned physics in high school so I know all the terms.
In my ...
1
vote
1answer
48 views
Disregarding drag force that affects pop-up lightweight ball
Is it possible to disregard drag force of water with no viscosity that affects lightweight pop-up ball (its weight is assumed to be zero)? There is a discussion, on which I consider that although ...
1
vote
0answers
48 views
Fading transition and rotation of and object in 2D
I'm looking for sources about I guess dynamics subject.
The model I'd like to solve is reduced to a question of:
How does a force applied on a certain point of an object results in both fading ...
5
votes
3answers
958 views
Block on a block problem, with friction
Consider two blocks, one on top of the other on a frictionless table, with masses $m_1$ and $m_2$ respectively. There is appreciable friction between the blocks, with coefficients $\mu_s$ and $\mu_k$ ...
3
votes
1answer
225 views
How is Normal Force on Table affected by two Blocks sliding on Triangle?
Suppose we have a triangle with mass M as shown:
Clearly, the normal force of from the system to the table is $Mg$.
But what if we added two blocks of equal mass m on sides BC and AC of triangle ...
1
vote
1answer
132 views
Force and Torque Question on an isolated system
If there's a rigid rod in space, and you give some external force perpendicular to the rod at one of the ends for a short time, what happens?
Specifically:
What dependence does the moment of inertia ...
2
votes
2answers
93 views
Forces involved in strapping something down
Say I have a hollow cylinder and I wanted to strap it down to the bed of a truck. I would tension the strap on one end, and it would exert a force on the cylinder. My intuition tells me that the strap ...
0
votes
1answer
210 views
If 2 charges have the same sign, the coulomb force is positive but repulsive, while with 2 masses the gravitational force is positive but attractive
If you have two point objects both the same positive charge and both of the same mass at a distance $r$ from each other.
The force between them due to gravity is $F_g=\frac{Gmm}{r^2}$ and $F_g$ is ...
0
votes
0answers
32 views
How can I determine the magnetic nature of three sealed boxes? [closed]
For my Physics class my partner and I have to do a lab assignment where we have to determine the magnetic nature of contents of three sealed boxes. My question is how can I write this information down ...
0
votes
0answers
50 views
Atomic force microscopy
I have these questions about force spectroscopy which I can't answer:
What is the basic principle of single molecule force spectroscopy and what is the main difference with chemical force microscopy? ...
12
votes
1answer
414 views
Do modern Formula One cars produce enough down-force to drive upside-down?
For example, if they were driving at top speed through a long tunnel, could they transition to and stay on the ceiling?
1
vote
2answers
119 views
How does this chair move?
I have a chair like this(shown in figure). I was kneeling on the part where we sit. I just gave a sudden push to the part where we rest the back, without moving my legs. I found that the chair is ...
8
votes
3answers
603 views
Is the normal force a conservative force?
Most of the time the normal force doesn't do any work because it's perpendicular to the direction of motion but if it does do work, would it be conservative or non-conservative?
For example, consider ...
2
votes
1answer
115 views
Swords, impacts and elasticity for a noob
So I'm a game developer and I'm trying to understand some (extremely) basic facts of impact mechanics. I had read something entitled Dynamics of Hand-Held Impact Weapons, but it was a bit too ...
0
votes
0answers
229 views
Torque required to rotate Drum [closed]
What Torque will require to rotate a Drum about horizontal axis XX.
Drum is filled with industrial Oil.
Weight of filled drum is $W=300 kg$.
Length of Drum $(L)=900mm$
and Diameter of Drum is ...
8
votes
2answers
249 views
What IS Color Charge?
This question has been asked twice already, with very detailed answers. After reading those answers, I am left with one more question: what is color charge?
It has nothing to do with colored light, ...
0
votes
0answers
165 views
Torque required to rotate sand mixer [closed]
the given data is-
Mixer having one impeller(rotor) rotating in horizontal plane about vertical axis.
capacity of mixer to design $C = 250kg$
rotor dia. $D = 45" = 1143mm$
friction coefficient ...
0
votes
0answers
314 views
How to find Rotational and Translational Equilibrium of Hanging Masses on a Bar?
I am making a hanging mobile which needs to be done mathematically by calculating torque. The problem is, I can't seem to figure out how to solve for the distance of the two masses from the pivot ...
2
votes
1answer
88 views
Forces: Worth worrying anything?
I am a general physics student, I had a question in my text-book and according to it two students having gravitational attraction between them = ($6.67\cdot10^-8\ \mathrm{Nm}^2/\mathrm{kg}^2$) is not ...
1
vote
1answer
223 views
Gravity force strength in 1D, 2D, 3D and higher spatial dimensions
Let's say that we want to measure the gravity force in 1D, 2D, 3D and higher spatial dimensions.
Will we get the same force strength in the first 3 dimensions and then it will go up? How about if ...
3
votes
2answers
189 views
Do we exert more force when we walk?
When we walk, is the magnitude of the earth's force on us greater than if we were standing still?
2
votes
1answer
78 views
Vertical Load Reactions On A Ramp
Hello,
I'm working on a small hardware project.
I have two load sensors located at distance $S_1$ ($x=0$) and $S_2$. Assuming we ignore the weight of the ramp ...
What is the load on $S_1$ and ...
4
votes
2answers
141 views
Is Brian Cox right to claim that Gravity is a strong force for large masses, is it wrong, or is it only a matter of interpretation?
I watched a program of his in which it was claimed that since mass bends space in accordance to General Relativity, then in the case of very large stars it becomes a strong force to the point of being ...
