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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350 views

Stresses on an inclined plane

Background This issue has been bothering me for a few days now. It's actually part of my homework, but I've already finished them and in a sense they're not part of the question here. What I would ...
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4answers
554 views

Acceleration of a car in a collision?

For example because of newton law $F=ma$ force is acceleration times mass but if I go at a high constant velocity ($900\: \mathrm{miles/hour}$) in my car for examples I have $0$ acceleration but if I ...
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1answer
153 views

2D. Force applied at angle to body, where translational vector will be directed?

I'm not a physicist and just making some research by the way of creating simple physics simulator, because of that, sorry if this is very dumb question, but I really need help with it. Let's assume ...
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0answers
41 views

A Global Measure on a Gravitational System

I am a computer science engineer and I am trying to simulate the gravity on my computer; several objects with different masses randomly distributed in a Three-dimensional space. I would like to ...
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2answers
436 views

Pressure difference between 2 points in an accelerated fluid

Consider a liquid in a tub and this tub is accelerated. And so the liquid will have a slanted surface. I am clear about finding pressure difference between two points in the fluid having same height ...
2
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2answers
329 views

Centre of gravity for a very tall building

Imagine a very tall building. Centre of gravity is defined as the point of application of force of gravity, right? Now, is the centre of gravity the same as centre of mass of this building? I am ...
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1answer
198 views

Capillary action in a slanted tube

Suppose there is a slanted capillary tube and a fluid rises in it. Why does the fluid rise to the same vertical height as when the tube is perfectly vertical? If I'm right surface tension force ...
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3answers
754 views

Relationship between power and max. speed

I'm talking about the maximum speed if let's say I have a car with the power $P = 1000 \text{W}$ and a force of friction of $5 \mbox{N}$ acting in the opposite direction. After some googling I found ...
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1answer
39 views

Proof about Newton: Homework [duplicate]

a mass hangs from three ropes (as shown in the Picture) can someone pleas help me with this?
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2answers
325 views

Vertical uniform circular motion.. can it really be uniform? [closed]

This is the picture in my mind: For centripetal force, I learned that: $T-mg\cos\theta= \frac{mv^2}{r}$ In vertical circular motion, the velocity is naturally going to decrease as kinetic energy ...
0
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4answers
264 views

Rolling motion of an accelerated body

I recently read in a book that static friction is zero for a rolling body, and this explains why it doesn't slow down the rolling body. However, if static friction is zero, how does the body grip the ...
0
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2answers
532 views

Will larger balls make a Newton's cradle swing more stable?

I got a rather small Netwon's cradle and when I start it, the effect is not very good since all the balls start to swing where the effect we want is obvious. The balls are small and I wonder if larger ...
0
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2answers
954 views

Physics of the inverted bottle dispenser

When you invert a water-bottle in a container, the water rises and then stops at a particular level --- as soon as it touches the hole of the inverted bottle. This will happen no matter how long ...
1
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1answer
241 views

How can spatially extended objects behave like point particles?

Wikipedia states: Sometimes due to specific combinations of properties extended objects behave as point-like even in their immediate vicinity. For example, spherical objects interacting in ...
0
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3answers
176 views

Inertia and Rocket Propulsion

We were taught in school that the law of inertia indicates that an object tend to stay the way it is, so if you throw something in space it will tend to go on forever and ever. The reason an object ...
1
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1answer
123 views

How would you quantify and predict the internal friction and efficiency of a bungee cord?

I am in an introductory physics class and we have been working with Gravitational Potential Energy, Elastic Potential Energy, Kinetic Energy and the Law of Conservation of Energy in relation to bungee ...
0
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2answers
118 views

Why doesn't Length of cycloid depend on speed of rolling?

We know that a point on the rim of a rolling body traces out a cycloid during one turn. Why is the length of the cycloid a constant = 8r. Shouldn't length of cycloid depend on speed of rolling body. ...
7
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4answers
2k views

Rotation of a slipping ladder

Imagine a ladder leaning against a wall. All surfaces are smooth. Hence the ladder will slip and fall. While falling it rotates because there are external torques acting on it. My question is about ...
3
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3answers
2k views

Why doesn't static friction decelerate a rolling body?

I know that static friction isn't the cause of deceleration of a rolling body. But if static friction is the only force in the horizontal direction, then shouldn't there be some acceleration produced ...
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1answer
80 views

friction between 2 bodies [closed]

There is a plank on which a block is kept. the block is given some velocity. Now if there is friction between block and plank it will act opposite to it's velocity for sure. but the plank is free to ...
0
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1answer
172 views

Newton's second law - infinite velocity?

Given the equation $$F_{\text{net}} = ma$$ Does this not imply that if the net force on a certain object is positive, its acceleration will also be positive, and theoretically this object would ...
0
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1answer
186 views

Moment of inertia of a disc with masses attached at the rim

Does the moment of inertia of a disc with some masses attached at the rim be the same as one without the attached masses? Or is it necessary to use parallel axis theorem to incorporate the moment of ...
0
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2answers
692 views

Normal reaction on wheels when car is taking a turn

I recently read in a book that for a car taking a turn on a horizontal surface, the normal reaction of the road on the outer wheels is always greater than the normal reaction on the inner wheels. ...
1
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2answers
242 views

Do heavier objects fall faster? [duplicate]

This question has been asked multiple times here and all over the internet yet I can't find a conclusive answer: Some claim that heavier objects do fall faster: Don't heavier objects actually fall ...
1
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2answers
548 views

Fluid Mechanics Piston Problem

The actual problem: A hydraulic car lift has a reservoir of fluid connected to two cylindrical fluid filled pipes. The pipe directly below the car has a diameter of 1.8 m. the pipe on which the ...
4
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2answers
121 views

The velocity of a cloud?

I noticed an unusually fast moving cloud this morning. My questions: What is the average velocity of a cloud on Earth? What is the greatest ever recorded cloud velocity? What factors affect the ...
3
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1answer
135 views

Paradox of angular velocity

For a torque-free symmetric top, the Inertia tensor has an inverse $I^{-1}$, and $L=I\omega$. Which implies that $\omega=I^{-1}L$. But since $I, L$ are constants, $\vec\omega$ is a constant. However, ...
2
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1answer
231 views

Why is body frame angular velocity nonzero?

This question is relevant to Euler's angles and Euler's equations for a rigid body. Why aren't $\omega_1$, $\omega_2$ and $\omega_3 = 0$ in the body frame? How can we measure $\vec\omega$?
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0answers
89 views

Finding kinetic friction coefficient

A box is thrown up an incline with degree $\alpha$. the kinetic-friction coefficient is $\mu_k$. the body returns back to its start point. a. prove ...
46
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6answers
3k views

Is there a way for an astronaut to rotate?

We know that if an imaginary astronaut is in the intergalactic (no external forces) and has an initial velocity zero, then he has is no way to change the position of his center of mass. The law of ...
0
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0answers
553 views

Elastic Ball Collision and contact angle

For a project I need to make a good simulation of balls moving around in a space. The project will be without any air drag and without losing energy in bounces. Since there is no way to lose energy ...
0
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2answers
268 views

Conservation of Angular Momentum and linear velocity

I have a problem where a cylinder is moving on a horizontal surface, starting with velocity $v_0$. It is given that its radius is $10\text{cm}$, its mass is $200\text g$ and the coefficient of ...
2
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2answers
694 views

Angular momentum of a translating and rotating body

If a rod is rotating about one end, does it have pure rotation or do you also consider the translation of centre of mass when calculating its angular momentum? Also, how would one calculate the ...
1
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1answer
75 views

Why does a particle fall in a straight line?

In Lagrangian Mechanics we choose the path of least action. Given a uniform gravitational field, and a particle of finite mass; and fixing two points the start & end-point we consider all paths ...
28
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6answers
2k views

Why are rockets so big?

I'm curious why rockets are so big in their size. Since both the gravitational potential one need to overcome in order to put thing into orbit, and the chemical energy burned from the fuel, are ...
1
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1answer
485 views

Newton's second law, gravity and buoyancy [closed]

A body of mass $m$ and volume $V$ is immersed into the sea. The body moves under the action of two forces: gravity and buoyancy (Archimedes). Gravity force has a magnitude $mg$, where $g$ is a ...
2
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1answer
194 views

Integration on a general equation for instantaneous angular acceleration

An equation for instantaneous angular acceleration is given as: $$ \alpha \equiv \lim_{\Delta t\to0}\frac{\Delta \omega}{\Delta t} = \frac{d\omega}{dt} $$ The text I am reading says writing this ...
0
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3answers
249 views

Will an object resting on a rotating platform move in a frictionless world?

Imagine that a pebble is placed on a uniformly rotating, frictionless disk. What will happen to this pebble? Will the disk slide under it and the pebble stay as is? Or will there be a centrifugal ...
0
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2answers
786 views

Direction of friction when a car turns

When a ball moves to the right, friction acts to oppose the motion, in other words, to the left. However, when a car travels around a bend, the friction acts in the perpendicular direction to the ...
1
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2answers
181 views

Newton's third Law?

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body. Newton's third ...
3
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2answers
90 views

Work and energy problem [closed]

I am trying to solve the problem (see image), my concern is about the 2 factor, can anyone please help me understand this.
0
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1answer
377 views

Will a free-falling rod (without drag) rotate?

When we consider a bicycle is turning on a flat plane, we know that there is friction, which provide centripetal force on the bicycle. And we know that the bicycle is no longer perpendicular to the ...
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2answers
198 views

Is two cars colliding at 25 mph the same as one car colliding into a wall at 50 mph in reference to injuries?

This question has been asked using 50 & 100 mph reference, see this Phys.SE post and links therein. However, I am interested in the potential injuries to occupants of the autos. As the one going ...
1
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2answers
183 views

Tension in vertical circular motion

In vertical circular motion we conserve energy for calculating velocities at a point (if initial velocity given). But, energy can only be conserved when forces are conservative. Tension is not a ...
1
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1answer
862 views

Tension on either side of a massive pulley?

When a pulley has mass, why is tension on both the sides different? Why don't we consider rotation of pulley when it is massless?
0
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1answer
135 views

Missing centrifugal acceleration

I am trying to get correct equations for acceleration of a point in reference frame A, given position, velocity and acceleration in rotating reference frame B. Let $\mathbf{x}_A(t)$, ...
2
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2answers
199 views

Can a massless rope accelerate?

Suppose I have an Atwood machine, that is, two different masses connected with an inextensible, massless rope over a pulley. Assuming no friction between the rope and the pulley, the heavier mass will ...
1
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2answers
424 views

Why do orbital speeds decrease further away from the focus?

Why do orbital speeds decrease further away from the focus? A simple question, but I want to make sure I am understanding this correctly: Is it ONLY a function of the gravity well? As in, the ...
1
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3answers
352 views

Effect of incoming force on linear vs. angular velocity

First of all, I should note that I'm a programmer and have only an extremely basic understanding of physics; I only know how to explain my question in layman's terms and I apologize if I'm unclear or ...
0
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1answer
117 views

Can the phrase “Terminal Velocity” be used to describe non-gravity situations?

According to Wikipedia: [Terminal Velocity] is the velocity of the object when the sum of the drag force (Fd) and buoyancy equals the downward force of gravity (FG) acting on the object. Since ...