# Questions tagged [newtonian-mechanics]

Newtonian mechanics discusses the movement of classical bodies under the influence of forces by applying Newton’s three laws. For more general concepts, use [classical-mechanics]. For Newton’s description of gravity, use [newtonian-gravity].

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### What actually causes damping in a damped SHM?

We know and have been taught that due to friction on the surface of maybe a spring mass system, the body faces damping. But what is bothering me, is the fact that force due to damping is proportional ...
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### When Two blocks are connected to a spring then there common velocity will always be equal to the velocity of their centre of mass? [closed]

We have two blocks connected to a spring at maximum compression the velocity of both the blocks is equal.will this equal velocity be always equal to the velocity of centre of mass of the two blocks?
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### Does the object's motion trajectory have to be along the inclined plane?

let’s say we have a frictionless inclined plane The angle between it and the frictionless Horizontal desktop is “$θ$”. And we have a very small object that can be considered as a mass point which has ...
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### What is the natural frequency of the system? [closed]

The natural frequency equation is $\omega_n =\sqrt{\frac{k}{m}}$ and the general form of a spring and mass system is $x’’+\frac{k}{m}x=0$ For this particular system I found the natural frequency to be ...
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### Calculating spring constant of a coupled double pendulum from a video [closed]

So basically would it be possible to calculate the the spring constant of a double pendulum using only a video of 2 such similar pendulums. If we know that the mass of a each bob is say 1 kg for ...
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### Who exactly decided to keep the 1/2 in the KE formula? [closed]

Who exactly stated or decided to have the 1/2 in ke formula?
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### Help me understand jerk of a falling object hitting an "ideal foam"

I'm trying to calculate the theoretical minimum thickness of an "ideal foam" for a given jerk and acceleration limit. Say we have a ball in free fall from 1.83 meter, reaching 6 m/s. It then ...
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### Why must the net force on the surface of water spinning in a bucket be perpendicular to the surface?

I learnt about the derivation of the shape of water in a spinning (constant speed) bucket. It's a parabola, however the explanations all assume the net force (centripetal/centrifugal and gravity) is ...
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### Is the concept of Lagrange points compatible with mainstream physics? [closed]

Take a point in between two bodies. The gravity cancels out to zero. A satellite has potential energy due to its proximity to a planet. However, when at the Lagrange point it cannot move because it's ...
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### Self-confinement of $N$-body gravitational systems

Consider $N=2$ point particles (each having unit mass) interacting via Newtonian gravity in the usual 3-dimensional space. There is a simple criterion to assess whether the system is bounded or not: ...
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Below is a question from my class notes from the topic $1$D Kinematics: A ball of mass $m$ is thrown vertically upwards with an initial speed $v_0$. Air resistance is given by $\vec{a_{res}}=-k\vec{v}... • 113 0 votes 0 answers 61 views ### How Strong Do tidal force gotta be to pull debris off a planet? How Strong do Tidal forces have to be to rip stuff out of a planet. I got this question And when i equate the tidal forces which acording to newtonian gravity gets around at max 2GMr/R^3 But my ... • 21 0 votes 4 answers 91 views ### Trying to explain why$W = ΔKE$and not$ΔE$[duplicate] I read this and started to think; Confusion about the total work done on an object applied by an upward force I understand the work-kinetic energy theorem, but this specific problem is causing me ... 3 votes 2 answers 843 views ### A thought experiment regarding elliptical orbits Say I'm in a circular orbit around the Earth. I give my motor a burn in the tangental direction. My understanding is that my trajectory now becomes an ellipse, and if I want to enter a new, higher ... • 141 0 votes 0 answers 33 views ### Ideal Pattern of Thrust on rolling body [closed] What Should be the idea pattern of switching a rocket engine attached to a rolling body on and off. So that it receives the maximum forward thrust. assuming that the ground has sufficient friction. ... • 21 -1 votes 0 answers 28 views ### What's change in height of mass on string when horizontal force is applied? [closed] If you have a 4kg mass hanging from a 0.35m light inextensible string and apply a 30N force horizontal to it, what is its vertical displacement? (assume g = 10 since this ought to be done without a ... 2 votes 6 answers 1k views ### Sum of the individual kinetic energies of the particles which make the system the same as the K.E. of the center of mass? What's bad in my reasoning? I have one idea, but I'm not sure it's true. According to Newton's second law, we have: $$F_{ext} = \sum m_i \cdot a_i \tag{1}$$ (where$i$denotes all the particles of the system), or: $$F_{ext} = ... • 648 1 vote 2 answers 62 views ### Does it take longer for the ball to rise to its maximum height or to fall from its maximum height back to the height from which it was thrown? [duplicate] A ball of mass M is thrown vertically upward with an initial speed of v o. It experiences a force of air resistance given by F = -kv, where k is a positive constant. The positive direction for all ... • 11 -1 votes 2 answers 37 views ### Why tension in a spring is equal to spring force If a spring is connected to a string then how tension and spring force are equal 0 votes 1 answer 52 views ### How does a motorbike ride on walls? I was looking at this question on the PAT 2020 and when looking at the answer I didn't understand why friction can be ignored. I first thought that friction was cancelling out weight to prevent it ... 1 vote 2 answers 80 views ### What are the different conditions for the Newtonian limit of General Relativity and for Special Relativity? Both the Newtonian limit and Special Relativity seem to be limits of General Relativity, but they are not the same limit. They occur when there is weaker gravity, but do they differ when the relative ... 0 votes 1 answer 26 views ### Where does the COM of a bungee jumper lie? I came across the following problem in one of the books i was solving, In bungee jumping, a performer ties on end of an elastic cord with his feet and the other end to a fixed support on a very high ... 0 votes 0 answers 28 views ### Can we derive instantaneous horizontal velocity by getting instantaneous tangential velocity? [closed] I have been stuck on this problem: I have been able to all of them except Problem 38. I think we are expected to solve this with just kinematics and dynamics. The approach I used is different than ... 1 vote 3 answers 149 views ### Is the definition of inertial reference frame circular? In elementary physics classes, inertial reference frames are defined as a coordinate system which is in constant rectilinear motion (or at least that is how it was defined by my professor). How then ... 0 votes 1 answer 48 views ### No net torque about principal axis I’m trying to follow the proof for why no net torque is required to sustain constant rotation about a principal axis. I am confused by the proof by contradiction above. How does “rotating the axis and ... 1 vote 1 answer 46 views ### Energy, and work applied by external/ non-conservative force I have two doubts. One regarding the equation of work and energy relationship. The first doubt is the statement of the realtionship itself. In some arguments, they mention that$$ E_{k1}+E_{p1}+W_{nc}=... -2 votes 1 answer 34 views ### Human exercise physics benchmarks. Force, Impulse, Work, Power. Calculation Spot Check [closed] If someone lifts 80 kg for 10 reps in 31.5 seconds, with a fitness machine that lifts the weight via a cord about 0.5 meters per rep, I am trying to calculate Force F (in N Newtons), Impulse J (in Ns ... 0 votes 1 answer 35 views ### Motion of two blocks connected by a spring [closed] Consider the following setup: Two elastic blocks of equal mass m and connected by a spring with a length l rest on a smooth horizontal floor. The coefficient of elasticity of the spring is k. A third ... 0 votes 1 answer 28 views ### How to calculate the force needed to make the shopping cart move? [closed] So I have this project, where I make a shopping-cart-gokart and I would like to calculate how much force is needed for the shopping cart to start moving. The biggest issue I had is that I could only ... • 15 0 votes 1 answer 50 views ### When we observe objects in a rotating frame, why do we apply centrifugal force radially outwards? [duplicate] Suppose we have small ball placed gently in a radial groove of a disk rotating at constant angular velocity. Why do we apply centrifugal force radially outwards? 0 votes 0 answers 39 views ### Rotations of car driving off of cliff [closed] I am struggling to approach and answer this problem, which to me feels deceptively difficult: A car of length L (measured between the rear and front wheels) is driven off a cliff (presumably perfectly ... • 17 -1 votes 6 answers 135 views ### Definition of impulse [closed] As far as I'm concerned, impulse is defined as $$\mathbf J=\int_{t_1}^{t_2}\mathbf F\,dt\tag1$$ But, since Newton's second law of motion states that$\mathbf F=\frac{d\mathbf p}{dt}$, this just ... • 179 -2 votes 0 answers 18 views ### What is the change in NCF from the top to the bottom of a ferris wheel? [closed] The radius of path followed on a ferris wheel is 120 m. The wheel completes one revolution in 20 minutes. Calculate the change in normal contact force from the top to the bottom. 1 vote 1 answer 72 views ### A confusion on a few parameters of two blocks connected with a spring [closed] Let's say I have two blocks of mass$m_1$and$m_2$and I connect it with a spring constant of$k$. I compress it to a distance$x_0$and release. I now wish to find the maximum speed. Now since ... 2 votes 1 answer 34 views ### Shadowing Lemma and Numerical Integration Shadowing lemma tells that any pseudo-trajectory (numerically integrated trajectory) from some initial condition$x_0$is the exact trajectory of a different initial condition$x_1$. Q: Is this ... -2 votes 0 answers 28 views ### Frictionless surface based questions [closed] A block of mass m slides on the wooden wedge, which in nirn slides backward on the horizontal surface. The acceleration of the block with respect to the wedge is. 1 vote 1 answer 39 views ### Monkey pulley problem doubt: why is tension less that weight of body without string break? * Why is the weight of the monkey more than the tension without the string breaking? Isn’t this not possible? 1 vote 1 answer 71 views ### How to Calculate the Stopping Distance of Train on a Complex Track [closed] I am attempting to determine when a train should begin braking to reach a certain point at a complete stop. There are several factors that need to be considered that make this more complicated and I ... • 13 1 vote 3 answers 109 views ### Identify the hollow sphere without making a sound! [closed] Recently I came across this problem, Can we use the principle of floating and sinking here? Both the spheres have the same mass. So,$\rho\cdot V=\text{constant}\implies \rho \propto \frac{1}{V}$... 0 votes 0 answers 31 views ### Question on air resistance [closed] I have a question about air resistance. The formula for the friction force is given by:$ F = \frac{1}{2} p_a \times c_w \times A \times v^2$I need some clarification regarding the relationship ... 0 votes 2 answers 53 views ### Why does$W_1$cancel out when$W_1$perpendicular to the surface and Normal Force cancel out? I recently learned that the weight that goes straight down drops out of the equation when you cancel the weight perpendicular to the Force Normal. I don't get what allows a person to drop the original ... 0 votes 2 answers 92 views ### Understanding change of momentum during collisions Following this question, I felt a little bit uncomfortable: It deals with a case of two equal masses$A, B$so that$A$'s speed is$v$and$B$stays at rest. Then A moves horizontally toward$B$until ... • 135 -2 votes 2 answers 34 views ### Work done by a spring on objects of different masses [closed] If a spring is compressed between two trolleys of masses m and 4m on a smooth one dimensional surface is released, will the work done on both masses be equal regardless of the trolleys' masses? 0 votes 0 answers 32 views ### How to transform generalised (polar) coordinates into cartesian coordinates? I have a set of observations$D=(q(t_i), p(t_i))$for$i=1,...,n_{data}$, where$q(t_i), p(t_i) \in R^n$. It is known that the$(q(t_i), p(t_i))$represent angles and angular momenta of a mechanical ... • 11 1 vote 1 answer 57 views ### Newtonian fields interaction Newtonian gravity is a linear approximation of a very weak field, such as gravitational waves. But why do gravitational waves interact with each other while Newtonian fields don't? 1 vote 1 answer 53 views ### Integrating Newton's$2^{nd}$law along path displacement in polar coordinates, handling separation of variables for second order differential terms Suppose an object is moving on a frictionless dome (which consists in an upper half circle of radius$R$) from the top of the dome (at$\theta=0$) to a position$\theta =\theta_f$, in which it has ... • 648 0 votes 1 answer 78 views ### Goldstein Chapter 6 Question I have a question about a potential error in the$3^{\mathrm{rd}}$edition of Goldstein's Classical Mechanics. In their exposition in Chapter 6 of small oscillations, the authors obtain the usual ... 0 votes 0 answers 30 views ### Why friction of a wheel is zero? [duplicate] MY physics teacher told us that friction is independent of surface area. but Also said that friction in a wheel is zero because the surface of wheel is in contact with wheel for only small amount of ... 1 vote 4 answers 126 views ### Does Newton's 3rd law hold true everytime? [duplicate] Well,I know (and was also told) Newton's third law is just conservation of momentum in disguise. And momentum is only conserved in a system when$\sum F_{ext}=0\$. Alright,suppose there is a system of ...
I recently came across the harmonic oscillator and the concept of reduced mass, i.e $$\mu = \frac{m_1m_2}{m_1 + m_2}$$ To begin, I understand the derivation from the point of view of sitting on one ...