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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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Related Accelerations Involving Wedge and Pulley

I would appreciate greatly your assistance on the following problem: The answer given in the book is: Acceleration of wedge: $0.7 \frac{m}{s^2}$. Reaction between wedge and horizontal plane: $173.25 N$. I would like to understand how these…
Edward C
  • 33
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Calculating velocity with no time given

I have the question "An egg falls from a nest 3.70m above the ground. Calculate its velocity when it hits the ground and the time it takes to fall". I know that velocity V = acceleration (a) X time (t) I also know that the acceleration in this…
Dan
  • 1,649
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Determine normal and sheer stresses in a sphere

$3D$ state of stress at point $(1, 1, -2)$ within a body relative to coordinate axis $(x_1, x_2, x_3)$ is given by $$ \begin{matrix} 2 & 3.5 & 2.5 \\ 3 & 0 & -1.5 \\ 2.5 & -1.5 & 1 \\ \end{matrix} MPa $$ Asked to…
vmark99
  • 29
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Potential energy regarding a central force

I am looking at my lecture notes for mechanics and it says that for a central force $\vec F=f(r)\hat r$, $$\vec F=-\nabla V $$ and so $$dV=-\vec F\cdot d\vec r$$ Then $$V=\int \vec F \cdot d\vec r=\int f(r)\frac{\vec r}{r}\cdot d\vec r $$ I'm fine…
MHW
  • 2,940
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Indifferent Tensor Field

An exercise in the continuum mechanics book by Gurtin says: A spatial tensor field $A$ is indifferent if, during any change in observer, A transforms according to $A^{*}(x^{*},t) = Q(t)A(x,t)Q(t)^{T}$. We have that $x^{*}(p,t) = Q(t)x(p,t)$. The…
Joe
  • 628
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Tension in a cable for a cuboidal block hinged at its top edge on a wall and lifted up on its hinge by a pulley connected to the cable.

A square $ABCD$ is actually a central cross-section of a cuboidal block of weight $W$. The block stands on the ground with $AD$ against a vertical wall. The edge through $A$ perpendicular to $ABCD$ is smoothly hinged to the wall. A cable is attached…
J132
  • 307
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A question on the conservation of energy between two objects.

A wedge of mass $M$ rests on a smooth horizontal surface. The face of the wedge is a smooth plane inclined at an angle α to the horizontal. A particle of mass $kM$ slides down the face of the wedge, starting from rest. At a later time $t$, the speed…
milanios
  • 47
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Mechanics - Conservation of Energy & Forces

The Question: Steel balls of mass=0.10kg are dropped from a height of ℎ=5.0m onto a smooth steel plate inclined at 45∘ to the vertical. If the balls are dropped one at a time at a rate of n=100 s^-1, what is the average force on the plate? You may…
Anthony Cheng
  • 25
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Fraction of original velocity in series of elastic collisions

I need to find the answer to this question: Three particles A, B, and C, with masses $m$, $2m$ and $3m \, \mathrm k \mathrm g$ respectively, lie at rest in that order in a straight line on a smooth horizontal table. The particle A is then projected…
imulsion
  • 869
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Simple Harmonic Motion - Particle Projection

Given $x=A\cos(\omega t) + B\sin(\omega t)$, how do you find the values of constants $A$ and $B$? I am aware that that depends on initial conditions, but I am unsure of the how. The initial conditions are $x(0)=2$ and $x'(0)=0$.
Clovers
  • 315
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Determine the Stress Vector on a plane given the normal?

Let $$\sigma=\left(\begin{array}{lcr} 1 & 1 & 0\\ 1&1&1\\0&1&1 \end{array}\right)$$ be the stress tensor. Find the stress vector acting on a plane through the point whose normal has components $\frac{1}{\sqrt{3}}(1,1,1)$ and deduce the component of…
Daniel Piggott
  • 75
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Find the smallest $t$ such that the object reaches the height of $96\text{ feet}$ at time $t$.

An object is tossing upwards with an initial speed of $64 \text{ feet/sec}$.Suppose the gravitational acceleration is $32\text{ feet/sec}^2$. Find the smallest $t$ such that the object reaches the height of $96\text{ feet}$ at time $t$. My…
Flip
  • 818
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constant deceleration problem

A train bracking with constant deceleration covers $1km$ in $20s$, and a second kilometre in $30s$ find the deceleration. Here is what I did: Since the deceleration is constant it would reach the average velocity in the middle of each $km$ So at…
H_Hassan
  • 807
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How can two horizontal forces acting at one point be at right angles?

I was looking at this exam question, and i had trouble figuring what it means. This question is on mechanics. Two horizontal forces X and Y act at a point O and are at right angles to each other.. I can't seem to understand how it is possible that…
dsa
  • 11
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Speed of a horizontal rotating lamina after a transfer of momentum from a body attached by a string

Four uniform rods, each of mass $m$ and length $2l$, are joined rigidly together to form a square frame $ABCD$ of side $2l$. The frame is placed with all four sides at rest on a smooth horizontal table. An inextensible string has one end attached …
Dan
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