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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Tension when two connected blocks are pulled in opposite directions [duplicate]

Suppose there exist two blocks A and B connected by a massless, inextensible cord. Both A and B have equal masses and are acted upon by equal forces in opposite directions. So, is the tension in the ...
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81 views

Calculating forces efficiently in Lagrangian formalism

I will Illustrate the question using an example problem: We have a mass $m$ connected to a mass $m$ by a rod of length $l$, and also to a mass $4m$ by another rod of length $l$. The rods are ...
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75 views

Contra-rotating propellers torques

Please look at the following mechanism for contra-rotating propellers: YouTube video When a CCW torque acts on the upper gear and a same torque acts on the lower gear (both seen from above), the ...
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336 views

Why doesn't a block rotate due to friction?

In a horizontal surface, a block (cube) is sliding due to a sudden push. When the block slides, there is frictional force which is acting on the block. Frictional force will have a torque around ...
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47 views

Inertial navigation system: am I doing it wrong?

I'm trying to develop an inertial navigation system. I can access data from an accelerometer sensor (acceleration on three axes) and gyroscope sensor (angular velocity on three axes). First of all, ...
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146 views

Which Force would help find the mass?

Two masses, A and B, are connected to a rope. A constant upward force 86.0N is applied to box A. Starting from rest, box B descends 12.1m in 4.70s . The tension in the rope connecting the two boxes is ...
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185 views

Why is speed/position relative but acceleration not? [duplicate]

I think i understand it now, if found this: link I know that position and speed are relative. There is no such thing as universal coordinates. Then why is acceleration absolute? Is the 3th and 4th ...
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399 views

Meaning of “Simple” in Simple Pendulum and Simple Harmonic Motion?

I have gone through the Phys.SE question Why is simple harmonic motion called so?. From the 1st answer of this Question it seems to me that another type of "Harmonic motion" is "Damped Harmonic ...
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68 views

UCM unidentified force

A train rounds a curve of radius 235 m (turning right). The train track is flat, and the train is traveling at a constant speed. A lamp in the train makes an angle to the vertical of 17.5 degrees. ...
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61 views

Finding at a distance from the Earth speed of satellite [closed]

A satellite at 8000 km from Earth where gravity is 6.4 m/s^2. What is the velocity of satellite? I don't the formula to find speed of satellite.
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56 views

Trouble with derivation in an equation for Newton's Law of Angular Motion

I'm an autodidact and can't follow the part after "it is easily seen that"... which is the 31st equation: Shouldn't it be: $m_i\,{\bf r}_i\times \frac{d^2{\bf r}_i }{dt^2}= \frac{d}{dt}(m_i r_i ...
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92 views

Question on Newton's law

I have heard my friends referring to quantity ma as the "force of acceleration" whereas my teacher told us it can't be referred as so. Is it correct to refer that quantity a force? If not, how can we ...
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92 views

Motion of a car rounding a bank

When a car is traveling round a banked track as fast as possible, it has a tendency to slip up the slope. Opposite in the case when the car travels slowly and has a tendency to slip down. Can ...
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295 views

Why neglect friction when computing torque?

There is a block of wood on a plank, with friction, and the block is moving down with uniform speed. They are asking what is the torque acting through the center of the block. My doubt is that ...
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2answers
337 views

Two springs and a mass between length L [closed]

I am trying to solve the problem that is depicted below; I am writing the equations with state variables as $x_2$ and $v_2$within the matrix form as; $$\begin{align*}\dot{x_2} &= v_2\\ \Sigma ...
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494 views

How do you get the equation of motion of a spherical pendulum WITHOUT using Lagrange or Hamilton equation?

How do you get the equation of motion of a spherical pendulum WITHOUT using Lagrange or Hamilton equation? I have been searching for a proper explanation but all websites use Lagrangian and I don't ...
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1answer
672 views

The choice of pivot point in non-equilibrium scenarios [duplicate]

It is true that under equilibrium condition, no matter what pivot point one choose, the resulting net torque will always be zero. I wonder if this principle apply to non-equilibrium scenarios as well, ...
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432 views

Geometry in diagonal matrix and inertia tensor

For this problem, can anyone explain to me why when $x_1$ axis is aligned with the diagonal of the cube, the resulting inertia tensor will become diagonal? How to interpret this result geometrically? ...
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183 views

Escape velocity problem

I was given a problem at school: How much Energy do we need to make a rocket of mass $m$ faster than the escape velocity so that it can travel in outer space? Here's how I worked: I know that ...
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1answer
114 views

Reference frame and centrifugal force

Imagine you are on a theme park ride in which you sit in a car and are spun around in a circle, basically like a giant centrifuge. An observer from the outside would say that there is no centrifugal ...
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375 views

Is the moment of a force the same about any point?

I know that when a body is is equilibrium There is zero resultant force in any direction, i.e. the sum of all the components of all the forces in any direction is zero The sum of the moments about ...
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2answers
272 views

Integrating the divergence of a velocity field (Fluid Mechanics)

I'm looking more for verification of my answer as I'm not 100% sure how valid my integration is here: If I have a 2-D incompressible fluid velocity field given by ...
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1answer
281 views

Center of mass of a cylinder from which liquid is flowing out

A cylindrical container is of mass M, radius R and height H. The cylinder is filled with a liquid of density D. The base of the cylinder has an outlet tap of radius r through which the liquid can flow ...
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560 views

Describing a motion of gyroscope with gimbal

Can you tell be how to set the equations to describe the motion of this machine in movie "Contact": https://www.youtube.com/watch?v=TSaO9VGjLXc This is gyroscope with gimbal, am I right?
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64 views

How can the tension force be computed to test if a shape is moving or not?

Source Given the coordinates of $n$ 3D joints ($1kg$ each) connected by $m$ rods. Assume rods have zero mass and joints with $z=0$ are fixed to the ground while others are free to move, will the ...
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104 views

What are Lagrange points in gravitation fields? [closed]

What are Lagrange points in gravitation fields? Additionally, what are their properties? For example, if a satellite or asteroid rested at a Lagrange-point.
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268 views

Calculating the time to stop a wheel with friction [closed]

I'm trying to solve the following problem, but i have no idea how to begin. A wheel of mass $M$, radius of gyration $k$, spins smoothly on a fixed horizontal axle of radius a which passes through ...
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1answer
141 views

Work done in non-uniform circular motion

In non-uniform circular motion, the work done by force should not be zero because tangential force acts on body. Is this correct? If I am wrong, please give a proper explanation.
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101 views

Is a scaled-up aircraft carrier 'ski-ramp' a viable system to impart enough velocity to significantly assist a spacecraft to orbit? [duplicate]

Not a boost straight up to escape velocity, just sufficient added momentum to make a significant economic saving on fuel cost, mass and complexity of a standard launch. It seems ludicrous to me how ...
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756 views

Max altitude of rocket [closed]

A rocket is launched perpendicularly with an initial acceleration of 10 m/s2, if the fuel runs out after 1 minute, what will be the maximum height reached by the rocket?
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70 views

Conservation of energy quick question

Say we had a particle moving in a frictionless funnel and was projected horizontally. If we had some initial conditions for the energy E, then would these conditions be the same always? For ...
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1answer
421 views

Finding angular momentum about the center of mass?

If we have a couple of particles of an equal, unknown mass: $$r_{+} = (c + e^{-Bt} \cos({\theta}))\textbf{x} + (d + e^{-Bt} \sin({\theta}))\textbf{y}$$ $$r_{-} = (c - e^{-Bt} ...
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131 views

Rigid body collision, 3 circles in contact

I'm working on a 2d physics simulation. It's a continuous time simulation, that is, it uses swept shapes over the time-frame and geometrical/vector 'analysis' to determine most immediate time of ...
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1answer
1k views

Explaining the restorative force in a bifilar pendulum

Ok so I am an A2 physics student, and for one of my pieces of coursework I conducted a practical investigation, my topic being the factors affecting the period and swing of a bifilar pendulum. The ...
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4answers
587 views

Can you lift yourself standing on a wooden block using pulley mounted on block? [duplicate]

I am new to this site. Please help me figure out this problem. Is it possible to lift oneself like shown in schematic? Waiting for good suggestions. Chirag
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296 views

Spring Damper System : Recoil Reduction

I am designing a man-"portable" 30mm sniper rifle. Although it may be classified as a anti-materiel cannon. I have the mass of the round in total, and the mass of the projectile leaving the barrel, ...
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117 views

Is speed squared constant?

q. A heavy particle is projected at speed $U$ at an angle $\alpha$ to the horizontal. The particle is subject to air resistance which is experimentally found to vary proportionally to the square ...
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54 views

Convert constant of gravitation to days and AUs

I'm working on a problem with celestial bodies and for my purpose days and AUs are more appropriate units than seconds and meters. So I tried to convert the constant of gravitation, $G$, like this: ...
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2answers
122 views

Vertical Circular Motion

I know that I can use conservation of energy to find the velocity of a particle at a point when it's travelling in a vertical circle by saying $$mgr(1-\cos{\theta})=\frac{1}{2}mv^2$$ then ...
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1answer
141 views

Reaction force of the ground beyond the equator

Let's imagine a person standing somewhere on Earth, but not on the equator, i.e. somewhere with a positive net value of latitude. Since the Earth spins around its axis and the person spins along, the ...
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2answers
76 views

Final position of an object after aplying several horizontal forces [closed]

I'm given an object with a starting position. Several horizontal forces are applied to this object one after the other for different amounts of time. How can I determine the final position $x$?
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152 views

Moment of inertia of a system in different cases

A rod of mass $m$ and length $l$ is pivoted at one end to ceiling and free to rotate in the vertical plane. A disc of radius $R$, which is less than $l$, can be fixed at its other end in 2 ways : ...
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69 views

The superposition of force (or acceleration) configurations

My question is quite specific as it refers to this article but I hope that someone here could help me. I cite the relevant part of the article: ... The second example consists of gravitational ...
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1answer
79 views

Regarding the centrifugal force in a 3-body system

In our lecture about general mechanics, we have treated the simplified 3-body system consisting of the Sun, the Earth and the Moon. We assumed that the moon does not have any influence on the Sun or ...
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106 views

Uniform Circular Motion: v = v_0 + (a_T)*t as a vector VS as a scalar equation

First, I'll explain my confusion, which may be enough for someone to clarify my misunderstanding. Second, to give context, I will give the homework problem (which I've solved successfully) which ...
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79 views

Some subtleties in direction of drag force

Consider a body released from a height $h$ and assume a drag force is linearly proportional to the velocity. Then by Newton's Second Law, $$m\mathbf{\dot{v}} = \mathbf{F_g} + \mathbf{F_{drag}} = ...
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407 views

Pseudo Force Other Than Centrifugal Force In A Rotating Frame

I read in HC Verma that if we are observing the motion of a body from a rotating frame and the body under the observation is NOT in motion with respect to our frame than centrifugal force is the ...
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297 views

Satellites and gravitation

A satellite with mass $m$ orbits a planet of mass $M$ in a circular path with radius $r$ and velocity $v$. Due to some internal technical failure, the satellite breaks into two, similar parts with ...
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438 views

Applying multiple forces to one object and calculate net movement and rotation?

I'm working on a small game as a hobby project, and I've run into a problem that would seem simple, to me, but that I can't find any information on or solution to. How would one go about figuring ...
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A reference frame must be non-moving?

I'm tough in school that a reference frame must be non-moving; For example if I take as reference frame the waves of the ocean, i will have the impression that i'm moving, but I'm not. But if movement ...