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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280 views

Acceleration: A ball sliding down the inside of a semicircular bowl

Edit: To clarify, this is a homework question. But I couldn't care less about getting the answer to this specific question as it's not even assigned yet. It looks interesting and I want to understand ...
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0answers
15 views

Why can this question about Centripetal Force not be answered in this way?

Here is the question: "A car travels round a bend which has radius 100 m and is banked at an angle of 20° to the horizontal. The car is travelling at a speed of 30 ms^-1. What is the least possible ...
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1answer
8 views

Condition for sliding of two blocks placed one over another and connected by spring

A constant force F is applied to smaller mass till M slides.The spring constant is k. Now it is asked to find k.I'm confused with the condition at which the block will start sliding.Can someone ...
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0answers
22 views

Action-Reaction pair in case of rocket accelerating in space

I understand Rocket works on Newton's 3rd law. So there has to be action-reaction pair acting on two different bodies. I know rockets accelerate in space, where there is nothing. So now I want to ...
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1answer
78 views

If the effects of gravity cannot travel faster than the “c”, does this mean we are only gravitationally bound by masses in our observable universe?

I'm 17 and fascinated by the differences and omissions Newton made in his equations of motion. However it makes sense that gravity can't travel faster than light because of the force-carrying ...
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1answer
53 views

Time to fall in a non-uniform gravitational field

In an uniform gravitational field the loss in potential energy (the work done) by gravity is given by $\text{-}mg\Delta h$ and the time to do so (assuming no friction and no initial velocity) is given ...
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3answers
3k views

First and Second Moment of Mass

I recently came across the definition of the Center of Mass of a system as the point about which the first moment of mass is zero. Further, it defined Moment of Inertia as the second moment of mass. ...
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2answers
33 views

Static friction and Kinetic friction

I can't seem to find this anywhere on the internet or on stack... Sadly. Very basic question: I have a block that is on a surface. The coefficient of static friction between the two is $0.3$, ...
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0answers
8 views

Path of puck through a turntable

I was looking a problem which tells me to consider myself standing on the ground beside a perfectly flat horizontal turntable rotating with constant angular velocity w. Then I lean over and shove a ...
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1answer
14 views

Object moving with 2 linear accelerations

Say I have an object moving with an acceleration of 5 m/s$^2$. At a certain point X, due to some forces, the acceleration of the object changes from 5 m/s$^2$ to 2 m/s$^2$. Would this change in ...
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2answers
39 views

Best coordinate system for Projectile motion [on hold]

What is the best coordinate system for describing the projectile motion? Rectangular coordinate system or n-t(normal and tangential) coordinate system.
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3answers
7k views

Rotating a stone with a string

Suppose we are given a stick and a stone tied to the stick by a string. Now if we rotate the stone around the stick the stone rises in height (see picture below). My question is which force accounts ...
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5answers
202 views

$F=ma$, so if acceleration is zero the force must also be zero?

I was just pushing a huge rock which I couldn't move at all. Given that the acceleration was zero as a result of my efforts, since $F=ma$, doesn't this mean that the force must also have been zero? ...
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1answer
84 views

Projectile, air resistance and wind

So for my school project I am working on a projectile simulator and air resistance. So I have looked at this. Equations for an object moving linearly but with air resistance taken into account? ...
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2answers
75 views

Conservation of angular momentum - exercise [on hold]

A sphere of mass $M$ is rotating with constant $w_0$ regarding the axis that intersects the north and south pole of the sphere. A bug of mass $m$ sits on the north pole and starts to walk along a ...
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1answer
2k views

Why is the mechanical advantage of a wedge = length of slope/ width?

Mechanical advantage is defined as Force Output/Force Input For a symmetrical wedge with the length of the slopes being equal and the width being the distance between the end points, the articles ...
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0answers
16 views

Simulating the rudder of a ship? [duplicate]

Assuming a calm body of water, what would be the correct way to calculate the force to turn a ship based on the angle of its rudder? I've read this post which I'm not fully clear on. For instance, ...
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2answers
854 views

Apparent violation of Newton's 3rd law and the conservation of angular momentum for a pair of charged particles interacting magnetically

Consider a system of the two identical point positive charges situated in the space (isolated from influence of any other external fields) as shown in the figure.Particle1 is at (a,a,0) and Particle2 ...
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1answer
136 views

What factors affect the velocity of an object moving down an inclined plane?

If you have a small toy car rolling down an wooden plank, what factors would increase or decrease the velocity of said car. In the experiment my team originally stated that adding mass to the car ...
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0answers
20 views

Finding displacement of spring [on hold]

Q) A block lies on a horizontal frictionless surface, and the spring constant is $50\,\mathrm{N/m}$. Initially, the spring is at its relaxed length and the block is stationary at position $x=0$. ...
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4answers
86 views

Acceleration of a particle moving along a straight line

If a particle moves along a straight line, then can we say that the acceleration should be zero? and if not, then why? If the equation of the motion is linear, then the velocity is constant and if ...
9
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3answers
560 views

Can Lagrangian mechanics be justified without referring to Newtonian mechanics?

Are there any ways of justifying Lagrangian mechanics as a foundation of classical physics, without referring to Newtonian mechanics? In other words, what is the deeper reason or intuition why ...
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0answers
21 views

Max speed of a turning disk for an object to stay at rest [on hold]

A coin is at rest relative to a disk moving with a angular speed of w: The coin weighs 0.010 kg The distance of the coin to the center of the disk is of 0.20 m The static friction is of 0.45N ...
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9answers
1k views

Did relativity make Newtonian mechanics obsolete?

Did Einstein completely prove Newton wrong? If so, why we apply Newtonian mechanics even today? Because Newton said that time is absolute and Einstein suggested it relative? So, if fundamentals are ...
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2answers
43 views

How can tangential acceleration from a radial force be explained?

A mass is attached to a rope, and put into a circular motion. If I pull the string from the center, the tangential speed of the mass will increase (by conservation of angular momentum). I am ...
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0answers
12 views

Sliding ladder kinetic energy in generalised coordinates [on hold]

This is a problem from Hand and Finchs' Analytical Mechanics, in a chapter looking at holonomic constraints and generalised coordinates in Lagrangian Mechanics. A ladder of length $L$ and mass $M$ ...
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8answers
7k views

Why doesn't a bike/bicycle fall if going with a high speed?

Why does a bike/bicycle fall when its speed is very low or close to zero and is balanced when going with a high speed?
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2answers
211 views

Confused about elasticity and collisions

I was solving the following problem and the explanation to it confused me. There are two objects with mass $m$ and $M$, respectively. The object with mass $m$ has a velocity of $\sqrt{2gl}$ and ...
2
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2answers
144 views

Lagrange's equation implying Newton's 2nd law?

The typical first application of Lagrange's equation is showing that it implies Newton's law for a particle whose Lagrangian is $L=\frac{1}{2}mv^2-V(x)$. Plugging this Lagrangian into Lagrange's ...
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0answers
31 views

Conservation Laws and Isotropic Time

In most dynamics books I've read they refer to conservation laws and their associated symmetries. I know that the conservation of momentum is a result of the homogenity of space angular momentum is ...
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1answer
21 views

What can I say about a graph depicting orbit a particle has gone through? Acceleration VS friction

I have an orbit in which a particle is told to have gone through. There is a straight part, and a curved part. I am asked to mark the right statements, which are: a. Without any further data, there ...
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7answers
2k views

Is rotational motion relative to space?

Let's assume that there is nothing in the universe except Earth. If the Earth rotates on its axis as it does, then would we experience the effects of rotational motion like centrifugal force and ...
6
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3answers
356 views

Optimal speed for the water wheel

The hydroelectricity plants extract the potential energy of highly deployed massive object (water) as it falls down. Without turbine, all that energy would be converted into speed (kinetic energy) at ...
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2answers
169 views

Ball flying towards me - Newton's third law is violated?

I was trying to answer the question of the flying ball here on the basis of Newtons third law and Momentum conservation. Here is what I have tried. Lets take $m_1$ (the ball) hits $m_2$ (the man). ...
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0answers
45 views

Mechanical energy? [on hold]

A particle of mass $2\,\mathrm{kg}$ is attached to one end of a model spring that is hanging vertically from a fixed point O. The spring has stiffness $4$ and natural length $1\,\mathrm{m}$. ...
2
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1answer
92 views

Moving Around Space Without Propellant [on hold]

A mechanism as shown in following picture is floating freely in space. Concentrating on the main components first, which is the long rod in the middle with another 8 smaller rods connected to it, ...
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1answer
282 views

Why does the Nusselt Number for a Constant Surface Temperature, Thermally Fully Developed Circular Pipe Converge To a Constant of 3.66?

I have flow in a pipe with a constant surface temperature boundary condition. The velocity profile is fully developed and the temperature profile is also fully developed. In my textbook, it says that ...
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9answers
2k views

How to explain independence of momentum and energy conservation in elementary terms?

I'm trying to explain to someone learning elementary physics (16 year old) that linear momentum and energy are conserved independently. I'm not a professional physicist and haven't tried to explain ...
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1answer
19 views

What is meant by “method of approximate numerical method” or “method of digital computer” for solving the differential equation of resistive force?

I was reading "motion against resistive forces" in Newtonian Mechanics by A.P. French; here is the excerpt: [...] In general, the resistive force $\mathbf{R}$ is is a function of speed, so that ...
3
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2answers
250 views

Projectile motion maximum distance to origin

Is there an elegant or easy way to derive the maximum distance from the origin to a point of the parabola created by projectile motion (assume initial position is the origin)? Other than ...
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0answers
67 views

Centrifugal And Centripetal Forces [closed]

Imagine a long rod floating in space(negligible gravity). On this long rod are attached 8 other smaller rods with a massive sphere attached to them at the end. They are connected with the long rod ...
-4
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2answers
2k views

If there is no gravity, does that mean there's no mass as well?

I have demonstrated that weight only is measured based on the gravitational pull of where you live. For example, the gravity on the surface of Mars is three times smaller than the gravity on the ...
0
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1answer
39 views

Resultant forces on system of particle is zero , we can have?

This is how the specific question is framed? If the resultant of all the external forces acting on a system of particles is zero, then from an inertial frame, one can surely say that: 1: ...
12
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5answers
730 views

Compressibility and the form of Newton's second law in fluid mechanics

In deriving Euler's equations for fluid mechanics, in particular $$f=\rho \partial_t v +\rho v\cdot \nabla v$$ for some body force $f$ (e.g Landau & Lifschitz 2.3) one assumes the continuity ...
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1answer
41 views

Maximum range of projectile from elevation, simply?

Let us say you have project a ball at velocity $u$ from a cliff hight $h$, and we want to find the maximum range of the ball. Ok so you could do this using equations of motion (for constant ...
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2answers
582 views

Is my understanding of the mechanics of skidding correct?

I'm trying to understand the mechanics which determine if a car making a turn will skid. Are the following correct or incorrect: A vehicle making a turn will skid unless the centripetal force is ...
3
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4answers
1k views

Can internal forces do work?

My Mechanics textbook claims that the sum of the work by internal forces is not generally zero. translated to English the paragraph reads: Notice about the work by internal forces: the work by ...
2
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1answer
79 views

Understanding Millikan's oil-drop experiment

This is quoted from A.P. French's Newtonian Mechanicsabout Millikan's oil-drop experiment: The droplets randomly produced in a mist of oil vapor are of various sizes. The ones that Millikan found ...
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0answers
30 views

How does the elasticity of a ball influence its behaviour during collision?

The problem I am trying to solve is as follows: A football made of rubber with mass $m$ rolls on a table at speed $v$ and angular speed $\omega$ until it hits a player. Some sort of deformation ...
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0answers
11 views

How to calculate the steps needed for a motor to rotate a circular object in a pulley configuration? [closed]

I have a stepper motor with 200 steps per revolution and a pulleys configuration as following: 3 pulleys with 100 mm diameter each on 1184 mm PCD and are equally spaced (120 degrees) from each other. ...