Questions tagged [newtonian-mechanics]

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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Taking Honor Mechanics class in college this semester and It would be great to get your opinions on advanced textbooks compatible with such a class? [duplicate]

I used to like and think that Halliday and Resnick was the best, but I've heard it is not really advanced. What honors physics textbook would you recommend or is the one most used out there? Again, I'...
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When we can consider a body to be point sized?

In motion we idealize big object to be point sized. But we don't do it all the times. I am having some confusion on it. Please tell when we consider objects to be point sized?
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33 views

Will the rods rotate about the hinge after collision?

The problem is like this: two blocks(considered to be point masses) of masses $m$ are simultaneously moving with uniform velocities $v_0$ towards the rods and they hit the edges of rod and stick to it(...
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3answers
811 views

Is there such thing as a critical value for the coefficient of friction?

Is it possible for coefficient of friction to be so high that no matter what force is applied to an object, the object will never move? For example, if I have an incline and a box on the incline ...
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1answer
149 views

Effect of forces inside a sphere

What would be the effect of applying two parallel forces of the same value at opposite points of the equator inside a sphere? Common sense tells me that it wouldn't move, but it seems that it could ...
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48 views

Force on a Charge

I apologize, as this question is quite basic. Suppose we have a point mass of mass $m$. Suppose it is at position $r(t)$ at time $t$. Then the magnitude of the force on this mass is $\ddot r(t) m$ ...
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2answers
55 views

Strategy for a person throwing an object in zero G to maximize a velocity

If an astronaut is drifting away from a space station holding a wrench, they could throw it in the opposite direction in an attempt to get back. But if they do it wrong, they will only end up ...
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3answers
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Time reversal symmetry in the presence of friction

I was reading a paper on time reversal symmetry, and came across an example of a pendulum swinging in the presence of friction: When we consider the more realistic physical situation of a swinging ...
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59 views

Weight at Poles and Equator Wrong?

Recently, I was thinking about the acceleration due to gravity on Earth when I remembered that I was taught that you weigh less at the equator because a fictitious centrifugal force "throws" you off ...
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Force of tension on both sides of one string- 2 questions

Here's something I want to ask you guys about: (source: mechanikaklasyczna.prv.pl) Many times downward N1 and N2 are ignored in exercises. Why? If forces of tension are balanced by each other, ...
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Why are velocity and kinetic energy not proportional? [duplicate]

In the equation $E_k=\frac12mv^2$ the fact that the kinetic energy of a moving object is not proportional to it's velocity seems counter-intuitive to me. Put another way, it seems intuitive to me ...
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Relation between the conservation of Energy and the conservation of Momentum?

I just learn about the momentum and it conservative attribute in a closed and isolate system and there is something I don't understand when I relate it to the conservation of the energy Considering ...
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From volume density to surface density

Let us say we have a volume $V$ having a volumetric mass(charge) density $\rho(x,y,z)$. Suppose we have a smooth surface $S$ within the volume with a surface mass(charge) density $\sigma(x,y,z)$, if ...
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A question about the physics of asteroid deflection [on hold]

A lot of scientists considered the problem of asteroid deflection.  So here is a question about this. Kinetic weapons are a well defined/studied  notion: A few words about the Orion project : ...
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2answers
145 views

Effect of wall friction on stagnation pressure and temperature

We have incompressible air flowing through a cylindrical pipe, from section A to section B. The process is considered to be stationary. My theory book says that, because of the frictional losses on ...
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1answer
446 views

Force balance for belt-pulley-mass model (2nd order response system)

I am trying to model a mass being driven by a motor (Angular acceleration $\dot{\omega}$ and shaft-polar modulus $J$) with belts and pulleys. This is then being compared to numerical simulations. I ...
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3answers
140 views

Potential energy of a spring thought experiment

Just wondering if I am using the concept of potential energy and conservation of energy correctly in the following thought experiment. Lets say we take a compressed spring into space. If we attach a ...
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3answers
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How does the normal force change *while* I'm lifting a heavy object?

A heavy weight is resting on a surface with, with the normal force equal to the weight. So the object is stationary. (W = N) Now I try to lift the heavy object so I'm exerting some upward force U. ...
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Why are arched bridges stronger than flat bridges?

To keep the question brief: in bridge design, why is the arch structure favoured compared to a simple flat one? In other words, how does the curved platform alter the force decomposition of the load ...
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2answers
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Maximum range of a projectile (launched from an elevation) [closed]

If a projectile is launched at a speed $u$ from a height $H$ above the horizontal axis, and air resistance is ignored, the maximum range of the projectile is $R_{max}=\frac ug\sqrt{u^2+2gH}$, ...
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Could an electric centrifugal fan in space be used to propel a substance to create force?

Would an electric centrifugal-force fan (like that found in a blower motor) work in space to create force, by putting a substance (like silica sand or something slippery) through the centrifugal fan ...
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1answer
37 views

Visualizing Uncertainties

I am making an uncertainty exercise from a simple Physics experiment based on deriving the equivalent spring constant for a series combination of springs. The mathematical model for the combination of ...
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2answers
1k views

Pressurized tank emptying over time through a given area

I having difficulty wrapping my head around a concept that I wish to solve. There exists a 10L tank of compressed air at 100psi. When an outlet hole of cross-sectional area of 0.115 $in^2$ is opened, ...
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1answer
629 views

What exactly does accelerometer measure on a vertical rotating disk?

I am trying to understand an aspect of rotational dynamics. I am having some trouble arriving at a solution. Consider a disk of uniform mass distribution, and radius R centered at the origin of an xy ...
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2answers
73 views

What does the term “Coriolis Effect” refer to?

I am familiar with Coriolis Effect referring to the effect that deflects eastward a projectile moving north on the rotating Earth. That is, as something applicable to north/south motion only. There ...
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2answers
411 views

How to estimate the impact force of a martial artist breaking bricks?

I was watching a martial artist breaking a stack of 9 out of 10 concrete bricks. I noticed that the last didn't break. It made me wonder if this would allow calculating the force dealt to be ...
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1answer
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Relative acceleration of bodies on opposite sides of a pulley

This is a problem that I encountered while solving problems related to constrained motion: With all the data given in the above question, I believe that the monkey just holds on to the rope and does ...
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1answer
3k views

Total kinetic energy of two particle system

Please help me understand this equation : Total kinetic energy of two particle system = K.E. of system w.r.t. centre of mass + K.E. of centre of mass Here's the derivation from my book : The author ...
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1answer
151 views

Simple Pendulum in Cartesian Coordinates

Riffing on the question in Simple Pendulum Why Generalized Coordinate Always Angle? , I'm trying to write down Newton's law for a simple pendulum in Cartesian coordinates. (I'm doing this as an ...
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Square gears pitch curve relationships [closed]

I am trying to design square gearset using MATLAB program. I have designed several ones (elliptical, eccentric, spiral, circular ....etc). But when I came to the square gears, I needed the ...
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5answers
559 views

Why we can't jump without bending our knees?

I observed it while trying to jump from my bed with my knees straightened and I failed to do it. I want to ask whether it is with all of us our it may be a medical issue with me? Why we can't jump ...
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2answers
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Varignon's theorem (Principle of moments) failure?

Varignon's theorem states that "If many coplanar forces are acting on a body, then the algebraic sum of torques of all the forces about a point in the plane of the forces is equal to the torque of ...
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Equations of motion due to gravity [duplicate]

This question has probably been asked before, but I couldn't immediately find anything with a search. Two masses of $m_1$ and $m_2$ are in space separated by a distance of $x$. They now accelerate ...
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1answer
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What is the acceleration of the large block? [closed]

The answer was given mg/(2M+m). I found this one and cannot find where i made the mistake....
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2answers
142 views

Work done in raising a rope at constant kinetic energy?

Usually the question I had was work done in raising a rope at constant speed. Obviously as you raise the rope, the mass changes over time. It'll be a simple integral. But what about work done in ...
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1answer
66 views

Friction as a cause of motion

Can anyone help me to understand why friction force is not opposing the resultant centripetal force acting on the box and instead being the cause of its existence?
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1answer
59 views

Projectile with linear drag [closed]

A particle with mass $m$ travels with speed $v_0$ and angle $\theta$ compared to the horizontal ground. Air resistance given as $F_R = -m \alpha v$, where $v$ is the particle's speed, is working ...
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2answers
61 views

Conservation of linear momentum with mass defect

Suppose we have an insulating container, like a perfect black body, which absorbs all the radiation coming from a radioactive element placed in the center (or some equivalent process like matter ...
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1answer
85 views

Acceleration in a system equal for every body — why?

A 1 kg cart can slide frictionlessly on the table. The black weights each weigh 1 kg. The pulleys are frictionless. The task is to determine the acceleration of the cart. For the left-most weight we ...
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3answers
122 views

What justifies the use of centre of mass?

Centre of mass gives the location where the 'weighted average' of all the elemental mass of a body acts. Considering that weighted average is one of the many statistical tools used to find the spread ...
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2answers
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How can an object move at constant velocity in 2 different instances, but in both instances the work done is the same?

Here's a bit more clarification. If I pick up an object at a constant velocity across distance h it takes me t seconds. If I pick up the same object at a constant velocity through distance h it takes ...
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3answers
162 views

Explain the relative motion between two particles of a rotating rigid body

A rigid body is defined as a collection of particles in which distance between each pair of particles remains constant. I was taught that the motion of any one particle of the rigid body with respect ...
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9answers
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Will a bathtub full of water weigh more if I add something that floats in the water?

Let's say I have a bucket or something bigger, like a bathtub full of water. I weigh that bath and get some value, $x$. Then I add a small boat made of wood to that bathtub that doesn't touch the ...
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1answer
148 views

The nature of Newtonian laws of motion

The first law of inertia deals with the motion of "ISOLATED BODIES". What are these isolated bodies? How do we know that a body is free from all forces? and eventually What do we mean by forces in ...
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1answer
382 views

Total angular momentum of a moving bike

I am having trouble understanding The principle behind adding the angular momentum of the wheels to the angular momentum of the centre of mass of the bike with respect to a coordinate system with its ...
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4answers
806 views

What is the effect of torque steering on a motorcycle with a long wheel base?

From experience, it appears motorcycles with a large wheelbase coupled with a long handlebar (say a modified Harley Ape Hangar) shows a noticeable tendency to veer to a side during acceleration vs a ...
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4answers
251 views

U-turn in Deep Space

While writing a physically realistic game ( "Asteroid Defender" ) a physical question came up whether Diag.1 or Diag.2 or Diag.3, correctly depicts reality. In deep space (away from other celestial ...
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Should all objects have equal acceleration to be considered a system?

Should all objects have equal acceleration to be considered a system?
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2answers
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Why do we need more power to do a job fast? [closed]

Let's assume we have two identical electric trains. One has a big electric motor (high power) and the other has small motor (low power). Let us assume the electric motors are of the same brand and ...
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1answer
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Determining the $z$-component of a force to maintain equilibrium?

I came across this problem in vector mechanics wherein I’m asked to determine the value of $d$ such that the tension in cables $AC$ and $AD$ is half the tension in $AB$. What I initially did was ...