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Questions tagged [classical-mechanics]

For questions on classical mechanics from a mathematical standpoint. This tag should not be the sole tag on a question.

Wikipedia says:

Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, as well as astronomical objects, such as spacecraft, planets, stars, and galaxies. Besides this, many specializations within the subject deal with gases, liquids, solids, and other specific sub-topics. Classical mechanics provides extremely accurate results as long as the domain of study is restricted to large objects and the speeds involved do not approach the speed of light.

For questions on classical mechanics from a mathematical standpoint. This tag should not be the sole tag on a question. Examples of other tags that might accompany this include , , and .

2097 questions
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Vertical Circular Motion

Please help, I'm struggling to find how to proceed with Energy methods, as I don't know how to get from the impulse given to a suitable initial velocity to use. "A particle, A, of mass 500g is attached to one end of a light inextensible string of…
Antonios
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Impulse in vertical circular motion

I'd really appreciate some help on starting a problem to do with vertical circular motion. I think once I know how to start I can work out the rest, but I honestly have no idea how to even attempt this. Given a resting pendulum of length s with a…
Antonios
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Mechanics Question: Where's my mistake?

I'm working through a problem and I get two different answers, one twice the other, depending on which method I use. I have a mass of $0.5$ Kg on a smooth plan (no friction). The plane is inclined at $30^{\circ}$ to the horizontal. The particle…
Fly by Night
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Find the acceleration and tension in pulley setup

Could anyone help me out with the following please. I am trying to find the the acceleration of A and the tension in the strings in the system in the following picture: I'll call the 3kg mass B and the movable pulley C and the 5kg mass D. I'll…
gnitsuk
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What is the acceleration of the given wedge?

Hi could anyone help me see my error, thanks. There is a diagram so I've attached the question as an image: Picture of question Here's my attempt: Resolving forces vertically: $100g + 6g\,cos(30) = N$ and as we are given $F=\frac{N}{7}$ so we…
gnitsuk
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Is my derivation of constant acceleration equations correct

I am posting my derivation since I have been very confused by how the books treat this topic. I hope someone can let me know if my derivation is correct. I will derive it in the most general manner without assuming things like $x(0)=0$…
Raghib
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Why does the author derive $v=v(0)+At$ in this way?

In the book "understanding physics" by Mansfield, the author derives the constant acceleration equations and at the start he derives the equation $v=v_0+A(t-t_0)$. I immediately noticed that setting $t=0$ in this gives $v(0)=v_0-At_0$, ie the…
Raghib
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Acceleration-time graph for a situation

The graph below is meant to represent an a-t graph for the following situation: A point moves away from origin at a slow constant velocity for 5s Then it moves away at a medium-fast constant velocity for 5s Then it stands still for 5s Then it moves…
Raghib
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Find the magnitude of the reaction force at the pivot

Consider the setup shown in the diagram below in which we have a uniform rod of mass $10\mathrm{kg}$ attached to the wall at $\mathrm{D}$ by a light inextensible string and pivoted at $\mathrm{A}$. A mass of $5\mathrm{kg}$ is attached at…
MHW
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Rigid Body Dynamics Problem

I state here a problem from S.L.Loney : A plank of mass $M$ is initially at rest along a line of greatest slope of a smooth plane inclined at an angle $α$ to the horizon and a man of mass $M'$ starting from the upper end walks down the plank so that…
Not Euler
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Trajectory of the three snails at the vertexes of an equilateral triangle approaching each other with a constant speed

There are three snails each at a vertex of an equilateral triangle "The first sets out towards the second, the second towards the third and the third towards the first, with a uniform speed of 5 cm min −1. During their motion each of them always…
ALICE
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Frictional forces

Can somebody help me in determine the direction of frictional forces at $A,B,C$? This is my reasoning. If friction was not present due to the weight, the rod AB will fall down and hence the point A should move to the right. Hence $F_a$ is to the…
mathnoob123
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Equilibrium of Forces

Solving this question will makes us realize that y-component of tension $T$ of the string satisfies the inequality $0
mathnoob123
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Direction of normal on the rod

Can somebody please assist me in finding the direction of the normal force exerted on B? (How is normal force at B also normal to the rod? ) There is no hint provided from which I can conclude the direction of normal force. Can somebody please…
mathnoob123
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Symmetry for a Lagrangian system

Given the Lagrangian $$L(x,y,\dot{x},\dot{y},t)=y^2\dot{x}^2+x^2\dot{y}^2+x+y+\dot{x}t+\dot{y}t $$ in the $x,y$ coordinates, I want to find some conserved quantities. Since there are no cyclic coordinates, I am searching for a symmetry for the…
Ginevra Carbone
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