Newtonian mechanics covers the discussion of the movement of classical bodies under the influence of forces by making use of Newton’s three laws. For more general discussion of energy, momentum conservation etc., use classical-mechanics, for Newton’s description of gravity, use newtonian-gravity.

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12k views

How do bicycle spokes work?

As you know, it is quite obvious that bicycle spokes attach the hub in the center to the rim. What else do they do? If you compare the wheels today with the ones from ancient times, there are more ...
2
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2answers
382 views

Is gravitation really a conservative force?

A rotating gyroscope that is mounted in a gimbal maintains its rotational axis relative to space when it is moved – and not to the surface of the earth, as illustrated below (the figure shows only the ...
12
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2answers
5k views

Are all central forces conservative? Wikipedia must be wrong

It might be just a simple definition problem but I learned in class that a central force does not necessarily need to be conservative and the German Wikipedia says so too. However, the English ...
3
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2answers
243 views

“Skidding” to Brake on a Skateboard

When people are skateboarding, sometimes they kind of push out their back foot when they turn while carving, causing the board to skid a bit. I was wondering the physics behind this, any details on ...
1
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0answers
47 views

What factors are influencing a woosh rocket?

Not sure if this is too much chemistry, but I'll try: If I fill a plastic bottle with a small amount of rubbing alcohol, shake it around and hold a match to the bottle neck, I'll get a flame wooshing ...
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2answers
760 views

What does the force mean in $dp/dt$ form?

One was to write Newton's laws is: $$F=\frac{dp}{dt}.$$ I don't understand what is the force there. I believe that $F$ is the net external force on the system. So supposedly I have a mass which is ...
2
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4answers
1k views

Does stopping the same bike and rider at the same velocity with the front brake require less energy than the back brake?

It's the same body made by the rider and the bike moving at the same speed. So, even though braking on the front/back alters the normal forces on the opposite wheels thus creating more friction with ...
5
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3answers
8k views

Does friction decrease as objects move faster against each other?

I was told that the faster two objects move against each other, the less the friction between them would be… compared to if they were moving slower. So does friction decrease when the body is moving ...
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1answer
40 views

Effects of vertical circular motion to the body weight

Our body weight will experience the differences when moving at constant speed in a vertical circular motion such as roller coaster. Why do we feel heavier when at the bottom of the loop and lighter ...
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3answers
1k views

Apparent weight vs. true weight

A question asks you to determine the relationship between true weight and apparent weight when an elevator that has descended from the 50th floor is coming to a halt at the first floor. I believe ...
-1
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1answer
127 views

Torque-direction of rotation

Taking moment about $A$, the mass of 2.0g and 0.50g is rotated in the clockwise direction is because they are both directed in downwards position? while $R2$ is acted in upward direction, so it is ...
1
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1answer
41 views

Are coefficients of friction invariant by switching the materials?

I don't have the ability to make the experiment to answer these questions : Let $A$ and $B$ be two materials. Is the static coefficient of friction of $A$ on $B$ equal to the static coefficient of ...
10
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2answers
2k views

Can a mouse rotating a wheel violate conservation of angular momentum?

I have been thinking on the following problem. Part I. Imagine we have a mouse enclosed in a rigid box. We placed the box on a frictionless surface (ice might be a good example). Can the box start ...
0
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0answers
62 views

Is it true that whenever any non rigid body moves, there must be a delay between the ends? [duplicate]

Very sorry if this is still considered a duplicate to this, but unfortunately the answer to this question cannot address this because mine is a nonrigid body and involve biological locomotion concepts ...
0
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1answer
52 views

Period to calculate the universal gravitational constant

To calculate the torsion constant in Cavendish experiment we need the period of it, so my question is if I need to measure the time the rod with two small spheres takes to do an oscillation (with an ...
10
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3answers
414 views

Is ordering players by height beneficial in a game of tug of war?

This can be considered a follow-up turn-around question for this similar question. I recently came across this interesting analysis of the game of tug of war. One of the closing discussions is the ...
-1
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1answer
254 views

Calculate orbit height from tangential velocity

Is it possible to calculate the altitude of a satellite orbiting a planet, just from the planet's mass and the satellite's velocity, assuming that the satellite is in a perfect circular orbit? If so, ...
0
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1answer
108 views

Are perpendicular components special in vectors?

We can split a vector (velocity/displacement vector) along any two directions as long as the resultant of the oblique components of the vector is same as my original vector. Similarly if we have to ...
1
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1answer
74 views

What is the velocity of Sun due to Earth alone?

If Earth and Sun were in a isolated system, will the Earth's motion around Sun will be similar? What will be Sun's and Earth's velocity when Earth is at its aphelion? Please note that it's not a ...
2
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1answer
38 views

Is motion along the $x$ and $y$ axises independent with quadratic drag?

It's often stated that motion in the $x$ and $y$ axises are independent, so that changing the $x$-velocity will not influence changes in the $y$-velocity. To me it seems that with quadratic drag (drag ...
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2answers
97 views

Exerting force upon oneself in space

In space, there is no friction or forces of resistance of any kind, so I would assume that if two people were in space and one of them punched or pushed the other, the person upon which the force was ...
0
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0answers
32 views

Anomalous orbit of pluto [duplicate]

Can anyone explain, why, like unlike all planets, Pluto does not have a regular orbit? Why does it have an orbit that meets the orbit of Neptune? Why does it never collides with Neptune? Is it ...
0
votes
1answer
292 views

Equations for a collision between two particles

Say I have two particles on a 2D plane, they have a x and y coordinate, a x and y velocity, a mass, a coefficient of restitution and a coefficient of friction. What formulae would I need to determine ...
3
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1answer
565 views

Feynman Lectures: Why a non-reversible weight lifting machine cannot lift higher that a reversible one?

Consider weight-lifting machines—machines which have the property that they lift one weight by lowering another. Let us also make a hypothesis: that there is no such thing as perpetual motion with ...
0
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2answers
163 views

Generalization of torque and angular momentum

Question: in the simple equations $\tau = r \times f$ and $L = r \times p$, what is the origin of the vector $r$? In many textbook discussions on rotation of a rigid body about a fixed axis, $r$ is ...
3
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5answers
8k views

Force applied to wheel in pure rolling motion at contact point with road [closed]

Suppose a wheel with radius $R$ is resting on a non-inclined surface. A torque $\tau$ is applied to the wheel center. In an attempt to prevent wheel from spinning, the ground applies a static friction ...
3
votes
1answer
72 views

Help understanding work

I have this problem: An object with 800kg mass is lifted up 2.4m by a force $F$. How much work does the Force do on the object (gravity is the only other force acting on the object)? From what ...
0
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3answers
278 views

Why does a change of direction imply an acceleration?

We know that it takes no energy to change the direction of a vector, we know also that it takes no energy to displace a body in motion if a push is applied exactly at a right angle on its center of ...
0
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1answer
228 views

Calculating time and speed change on downhill incline

I am trying to calculate the time and final speed if lets say a bike with constant speed of 20km/h of goes in this incline (downhill), what would be its speed after say $M$ meter ? I remember the ...
0
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2answers
152 views

Does an orbiting body accelerate?

Wikipedia says that : "Transverse acceleration (perpendicular to velocity) causes change in direction. If it is constant in magnitude and changing in direction with the velocity, we get a ...
0
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1answer
513 views

Can I convert Power to Force?

I just realized that I have some issues with physics: I cannot just convert Power to Force (different units), $P = F * v$. But am I not able to calculate the force on a car that accelerates with a ...
3
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2answers
198 views

Conceptual rolling

If you could roll a ball down a slope with friction, we would all know which direction the ball is rolling. However, say we have a frictionless slope and we roll the ball in the opposite direction and ...
10
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6answers
73k views

What is the difference between stress and pressure?

What is the difference between stress and pressure? Are there any intuitive examples that explain the difference between the two? How about an example of when pressure and stress are not equal?
0
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1answer
134 views

Newton's laws in non inertial frame

Suppose we take a two particle system in CM frame such that the particles are connected by a massless spring and a force $F$ is applied on one particle ($m_1$ and $m_2$. Let $F$ acting on $m_2$). Now ...
0
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1answer
41 views

How do I incoporate gyro information in my position and velocity calculation? [closed]

The velocity in 1 direction can be calculated as : $V_t=V_0+at$ And position could be calculated as $P_t=V_0t+1/2at^2$. Besides time, acceleration, I was also given information from 3 axis ...
2
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1answer
97 views

Damping a spring force

I'm modelling particles in a system using a spring and damper force. $$F= kx -cv$$ $x=x_i -x_f$, where $x_i$=centre of spring and $x_f$= displaced position. Above $x$ is the displacement and $v$ is ...
3
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0answers
92 views

Can one verify the Earth tide in his yard?

The ocean tide you can see on the coast. But the Earth tide beneath our feet is hardly perceivable. Is there any way to verify it in one's yard?
1
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3answers
112 views

How can i prove that $\frac{d\vec{p}}{dt} = \vec{F_{net}}$? [duplicate]

I could prove that $d\vec{p}/dt = m\vec{a}$, but how can I prove that $\vec{F_{net}}=d\vec{p}/dt$? Is force just defined by this expression? What is the rigorous definition of a general force? In my ...
0
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2answers
3k views

How to find speed from Newton's law?

I have a question about Newton's law. The question says block A(mass 2.25kg) rests on a tabletop. It is connected by a horizontal cord passing over a light, friction less pulley to hanging block ...
0
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1answer
91 views

Hooke's Law Problem [closed]

This question assumes that the spring obeys Hooke's law. Say we have a spring Length $L$. The energy of said spring when extended will be $E=(kx^2)/2$. The extension $x_1$ of said string would be $...
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2answers
1k views

Velocity required for Horizontal Rain

Related to my previous question - Change in appearance of liquid drop due to gravity... Ok, I think we all have noticed this practical phenomena (a kind of illusion though)... During rain (while we'...
1
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1answer
49 views

Particle hitting particles attached with springs [closed]

In classical mechanics if you have a particle moving in two dimensions and it hits a particle at rest although that particle is attached to a spring that is in turn attached to a third particle. ...
1
vote
1answer
403 views

How to calculate distance travelled while car is rolling, given start and end speed?

I'm trying to calculate the distance travelled by my Formula Student racecar if it starts at a certain speed, goes into Neutral (no acceleration, no brakes, just rolling on its wheels), and ends at ...
0
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0answers
116 views

Deriving differential equation of a cart moved by a motor

This is homework and I'm having some trouble getting started. How do I go from what's given to the form that they ask for? Normally in something like this I would try to balance torque, but I'm not ...
3
votes
2answers
646 views

“Suicide Burn” rocket problem [closed]

THIS IS NOT HOMEWORK. I'm actually in Physics I atm, and am an avid player of Kerbal Space Program. I hope to do my CS masters thesis several years from now on something space related. But none of ...
1
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3answers
499 views

Why dont we consider force exerted by atmospheric pressure in mechanics?

My school has started teaching fluid mechanics, and it really bugs me why we don't consider force exerted by atmospheric pressure in mechanics. I couldn't understand a word my teacher said. There is ...
0
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0answers
37 views

How Newton's third law is involved in a tug of war? [duplicate]

Using Newton's third law, we can say that each team applies the same force on the opposite team. Then how one wins? Is it due to ground friction?
0
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1answer
51 views

Vector representation of angular quantities?

In the world of pure rotation, a vector defines an axis of rotation, not a direction in which something moves. Does it means that angular quantities like angular momentum, angular speed, torque etc ...
-2
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1answer
124 views

Why Aristotle made mistake about motions law? [closed]

Hi I was studying Aristotle motions law and comparing them with Newton. He states that heavier body fall faster than slow ones. I really can't understand how he could committed such a mistake...I mean ...
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5answers
226 views

Why does solving $\mu mg = m \frac{v^2}{r}$ give the *max* possible velocity?

So here is the standard problem setup of a car turning on an unbanked road: A 1000 kg car is going around a curve with radius 30 meters. If the coefficient of friction between the car's tires ...