Classical mechanics is a physical theory describing the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars, and galaxies. For objects governed by classical mechanics, if the present state is known, it is possible to predict how it will move in the future (determinism), and how it has moved in the past (reversibility).
The earliest development of classical mechanics is often referred to as Newtonian mechanics. It consists of the physical concepts based on foundational works of Sir Isaac Newton, and the mathematical methods invented by Gottfried Wilhelm Leibniz, Joseph-Louis Lagrange, Leonhard Euler, and other contemporaries, in the 17th century to describe the motion of bodies under the influence of a system of forces. Later, more abstract methods were developed, leading to the reformulations of classical mechanics known as Lagrangian mechanics and Hamiltonian mechanics. These advances, made predominantly in the 18th and 19th centuries, extend substantially beyond earlier works, particularly through their use of analytical mechanics. They are, with some modification, also used in all areas of modern physics.
Classical mechanics provides extremely accurate results when studying large objects that are not extremely massive and speeds not approaching the speed of light. When the objects being examined have about the size of an atom diameter, it becomes necessary to introduce the other major sub-field of mechanics: quantum mechanics. To describe velocities that are not small compared to the speed of light, special relativity is needed. In cases where objects become extremely massive, general relativity becomes applicable. However, a number of modern sources do include relativistic mechanics in classical physics, which in their view represents classical mechanics in its most developed and accurate form.
Homework Statement
This is the problem 8.62(in screenshot) from Morin's textbook of Classical mechanics. I solved it using conservation of momentum in y direction. However in solution manual,he neglects the momentum in y direction by calling stick frictionless. What is this frictionless stick...
Homework Statement
The problem is in attached screenshot. Now,I solved this using force/torque method. However ,I got different solution as given in solution manual. Where I have gone wrong?
Homework EquationsThe Attempt at a Solution
Applying F=ma to cylinder:
$$mg-T=ma$$
Applying ##\tau =...
Homework Statement
This problem was originally posted on Physics Problems Q&A: http://physics.qandaexchange.com/?qa=616/friction-between-two-disks
Homework Equations
Second Newton's law for rotation:
$$\tau = I \alpha = RF$$
The Attempt at a Solution
I tried to solve this problem as...
Homework Statement
You buy a bottle of water in the store and place it on the conveyor belt with the longitudinal axis perpendicular to the direction of movement of the belt. Initially, both the belt and the bottle are at rest. We can approach the bottle as one cylinder with radius ##R##, mass...
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A train stands in the middle of a rotating disk with an initial angular velocity of
$\omega_i$. The mass of the train is m and the moment of inertia of the train-disk is I. At one point the train departs on a straight track to a distance R from the disk's centre. (R...
Homework Statement
A weight is suspended from a spring 50 cm long and stretches it by 1 cm. Take the other end of the spring in your hand and rotate the weight in a horizontal plane so that the spring is stretched by 10 cm. What is the velocity of the weight? (The force with which the stretched...
I have read in several popular physics texts that general relativity predicts that gravity deflects light, but that Newtonian mechanics, in contrast, predicts that the trajectory of light is not affected by gravity. However, I am very skeptical and confused about this result.
We of course have...
Homework Statement
The problem states that there is a father pulling a 100 lb sled with a force of 100 lb at some angle. At what angle does the father have to pull in order for the sled to accelerate at 25 ft/s^2? The coefficient of kinetic friction here is given as 0.04.
Homework Equations
F...
1. Homework Statement
A 60 kg block is pushed horizontally with just enough force to start its motion Accross a floor and the same force acts on it afterwards.The coefficient of static and sliding frictions are 0.5 and 0.4 respectively.
Find acceleration of the body.
Options
6m/s^2
4.9m/s^2...
What makes frictional force the centripetal force of a car turning along a curve?
As friction is the opposing force and acts anti-parallel so there is no component of frictional force towards the center,right? Then how can frictional force be centripetal force?
Many books sometimes for example define energy as quantity and sometimes as property. Also the definition of energy is the ability to do work or the meter of the ability to do work ? we define for example force as a quantity or as some quality and then we quantify this ?
For example F=ma means that the definition of force is m*a or the quantity of left side equals to the quantity of right side or both ? or kinetic energy..we know K=1/2mu^2 but is this the definition of kinetic energy or just the formula to calculate it ?
A particle of mass m in xy plane is attracted toward the origin with the force
$$\begin{align}\vec{f} = - \frac{k^{2} m}{r^{6}}\vec{r}\end{align}$$ where ##\vec r## is position vector of particle measured from origin. If it starts at position ##(a,0)## with speed $$v=\frac{k}{\sqrt{2} a^{2}}$$...
I studied the vector analysis in Arfken and Weber's textbook : Mathematical Methods for Physicists 5th edition.
In this book they give the definition of vectors in N dimensions as the following:
The set of ##N## quantities ##V_{j}## is said to be the components of an N-dimensional vector ##V##...
Homework Statement
A professional thrower projects a football straight up in the air.
1. Assuming there is no air drag on the football, find the speed of the football as a function of height as the ball goes up.
2. Assuming the air drag on the football varies linearly with speed, find the speed...
Homework Statement
Find the velocity ± and the position x as functions of the time t for a particle of mass m, which starts from rest at x =0 and t =0, subject to the following force functions:
(a) Fx = F0 + Ct
(b) Fx = F0 sin Ct Ct
(c) Fx = F0e^ct
where F0 and c are positive constants...
The situation:
The mass is pushed up an incline with an angle of 1 degree with an initial velocity of 1 m/s, and it comes back down to its original position.
The questions to answer:
What is the total distance the object travels on the frictionless inclined plane?
How long will the object...
Homework Statement
A bead slides under the influence of gravity on the frictionless interior surface of the paraboloid of revolution z = (x^2+y^2)/2a = r^2/2a Find the speed v_0 at which the bead will move in a horizontal circle of radius r_0 Find the frequency of small radial...
Homework Statement
Referring to the attached diagram, the object ABCD is kept in an isolated system where it is under no external influence of any kind.
A· An instantaneous force F acts along the edge BC of the block ABCD, where M is its mass, with its center of mass located at O...
<< Thread moved to the schoolwork forums from the technical forums, so no Homework Template is shown >>
The problem is a modified version of two basic block problems. This is my work so far, but I end up with two equations for acceleration from m1 and m2, I don't understand how to use both...
I have just begun my journey in Classical Mechanics with the book "An Introduction to Mechanics" by Kleppner and Kolenkow. I find myself stuck at Newton's first law. The book presents Newton's first law as follows:
"Newton's first law is an assertion that inertial frames exist."
The book also...
I'm looking for a source of harder mechanics problems, preferably with solutions. I'm supposed to use the Young and Freedman book, but I find it rather teadious and superficial; most problems don't match the difficulty and depth of the ones on the exam. I had my mid-term tests recently, and got...
Homework Statement
A block is placed inside a horizontal hollow cylinder. The cylinder is rotating with constant angular speed one revolution per second about its axis. The angular position of the block at which it begins to slide is 30° below the horizontal level passing through the center...
Homework Statement
A force F is applied on the bigger mass 'M', which results in the prevention of smaller masses M1 and M2 moving with respect to larger mass M. The mass 'M' slides smoothly on the frictionless surface. Find the magnitude of the force. The pulley is ideal also consider the...
Homework Statement
How do we determine a specific force mentioned in a question to be conservative or non-conservative?
2. Relevant data
Conservative force is a force whose work done does not depend on the path that is taken while doing it. Examples include electrostatic force, gravitational...
Homework Statement
Given an plate that has 2 pins attached to it. Each pin has a single balanced circular disc firmly attached to it. Each pin can rotate on their axis in both clockwise and anti clockwise direction. (See image below)
Now, assume the discs are rotating with the same angular...
I have a (somewhat) strange energy equation which has the following form:
KE = A + B W + C \exp(-D W),
where A,B,D are known constant, C is an unknown constant to be determined and kinetic and potential energy are given by KE and W respectively with W\equiv W(r) i.e. is a function of...
I've been working on a crude N-body simulator which allows N bodies of equal masses to interact gravitationally in 2 dimensions. My goal is to model the formation of Solar System.
Each body is modeled as a circle with a radius as a function of its mass, in such a way that all bodies have the...
http://www.pitt.edu/~jdnorton/Goodies/Dome/
I think that most wonderful point in this story is that the person who writes such texts is Distinguished Professor of University of Pittsburgh.
Nevertheless I believe that the question he stated up can confuse an undergraduate student and thus...
Homework Statement
The space shuttle is in a 300 km-high circular orbit. It needs to reach a 520 km - high circular orbit to catch the Hubble Space Telescope for repairs. The shuttle's mass is 6.5 E4 kg. Mass of the Earth = 5.98 E24 kg. Radius of Earth = 6.37 E6 m.
How much energy is required...
In the solution of this problem(121), dW = (kmgcosΦ + mgsinΦ) ds, where ds is the differential element along the curve. Now they have done kmg dscosΦ + mg ds(sinΦ) = kmgdx +mgdy. Makes sense intuitively, but I want to know how this is rigorous. What I'm thinking is, the curve is broken into N...
Homework Statement
An object with mass of m traveling in a circle rail ,when reached point A the object derailed and moved in a parabola path to point B and so on find the length of AB in term of R and theta. given that B is on the same horizontal level as A
Homework EquationsThe...
Homework Statement
There is a uniform slender bar which is suspended by two light inextensible strings and hangs in equilibrium. (if the mass and length of the bar are m and 2b )
Now, someone slightly knocks one end to make the bar rotate around the vertical axis with initial angular velocity...
Homework Statement
A rocket with initial mass of m0. The engine that can burn gas at a rate defined by m(t)=m0-αt, and expel gas at speed (relative to the rocket) of u(t)=u0-βt. Here, m0, α, u0, and β are all constants. Assume the lift-off from ground is immediate
a) The rocket speed v(t)=...
Homework Statement
In each of the diagrams (please see attached file (I am sorry for the rotated, the original was in normal form but when uploading it, it was somehow rotated)) and the description of each case below, a particle is moving on a smooth surface, so that the reaction force R acting...
Homework Statement
A cylindrical vessel of height ##H## and radius ##R## contains liquid of density ##\rho##. Determine the circumferential tension at a height ##h##; also determine its maximum and minimum values.
This is the scan of the original question(solved), I couldn't understand what...
Homework Statement
A chain of length ##l\lt \dfrac{\pi r }{2}## is placed on a smooth hemispherical surface of radius R with one of its ends fixed at the top of the hemisphere. What will be the tangential acceleration of the chain when it starts sliding down.
Homework EquationsThe Attempt at a...
A prisoner in jail decides to escape by sliding to freedom down a rope provided by an
accomplice. He attaches the top end of the rope to a hook outside his window; the
bottom end of the rope hangs clear of the ground. The rope has a mass of 10 kg, and the
prisoner has a mass of 70 kg. The...
Homework Statement
I'm trying to calculate the absolute lowest safe altitude above a planet's surface to start firing the thrusters on a simulated lander in order tot just reach vCraft = 0 at the planet's surface.
The force the craft's thrusters responsible for desceleration generate is...
Homework Statement
I need to find the period of small vertical oscillations about equilibrium position of a string whose motion can be described by the following equation:
d2x/dt2 = (-g/h)*x
Answer: 2π√(h/g)
Homework Equations
I know that the time period is given by the formula
T = 2πω where...
Homework Statement
It is a Matching Type Problem(a single entry in a column can be matched with more than one in the other column):-
A block is projected with an initial velocity ##v_{\text{Block}}## on a long conveyor belt moving with velocity ##v_{\text{Belt}}##(at that instant) having...
Homework Statement
Question :- A block of mass ##5 kg## is attached to a spring. The spring is stretched by ##10 cm## under the load of the block. A impulse is provided to the block such that it moves up with a velocity of ##2 m/s##. Find the height it will rise.
Homework Equations
##F_s =...
Homework Statement
Question :-
Two stars, each of a solar mass and radius ##10^7 m## are at a distance of ##10^{12} m## from each other. Find the speed of each star before collision if initial speed is negligible.
Homework Equations
$$V(r) = {-G Mm \over r}$$
The Attempt at a Solution...
Homework Statement
A solid sphere of density ##ρ## and radius ##R## is centered at the origin. It has a spherical cavity in it that is of radius ##R/4## and which is centered at ##(R/2, 0, 0)##, i.e. a small sphere of material has been removed from the large sphere. What is the the center of...
Homework Statement
Find the equation of motion of the object by setting the derivative of the total energy equal to zero.
Homework Equations
r(theta)=(Rcos(theta), Rsin(theta), q*theta)
v(theta)=dr/dt=(-Rsin(theta)dtheta/dt, Rcos(theta)dtheta/dt, q*dtheta/dt)
derivative of Total Energy =...
The following problem is from Sears and Zemansky's textbook.
A wooden rod of negligible mass and length 80.0 cm is pivoted about a horizontal axis through its center. A white rat with mass 0.500 kg clings to one end of the stick, and a mouse with mass 0.200 kg clings to the other end. The...
Homework Statement
A tube of length '##L##' is filled completely with an incompressible liquid of mass '##M##' and closed at both of the ends. The tube is then rotated in a horizontal plane about one of it's ends with a uniform angular velocity '##\omega##'. Then which of the following...
Homework Statement
A particle of mass ##m## rotates about ##Z-##axis in a circle of radius ##a## with a uniform angular speed ##\omega##. It is viewed from a frame rotating about the ##Z-##axis with a uniform angular speed ##\omega_0##. Find the centrifugal force on the particle.
Homework...
Homework Statement
A weightless string passes through a slit over a pulley. The slit offers frictional force '##f##' to the string. the string carries two weights having masses ##m_1## and ##m_2## where ##m_2 \gt m_1##, then find the acceleration of the weights.
Homework Equations...
Homework Statement
Find the maximum compression in the spring, if the lower block is shifted to rightwards with acceleration of '##a##'. All the surfaces are smooth.
Homework Equations
$$\vec{F}=m\vec{a}$$
$$\vec{F}_{sp}=k\vec{x}$$
The Attempt at a Solution
FBD of the upper block:
From...