Tagged Questions

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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1answer
40 views

Spring on a cart problem

The problem is two dimensional. At t = 0, a stationary cart at initial position (0,0) starts to accelerate with acceleration a in the negative "x-axis" direction. On the cart, there is an isosceles ...
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0answers
25 views

Why the sum of energy don't increase in this device?

The black arm is turning clockwise at $w1$. The blue axis is fixed to the ground. The grey cruz (grey arms) is turning at $w2$, with $w2 < w1$, so the grey cruz is turning around itself ...
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0answers
23 views

Theory books for physics upto Irodov level [duplicate]

Problems in Physics by IE Irodov is a very popular book amongst students for problem solving. It has very good problems. However, most of the popular high-school physics textbooks like Resnick ...
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0answers
19 views

Is there an applied force acting on the balloon? [duplicate]

A long string is running through a straw with a blown-up balloon taped onto the straw, and a penny taped onto the balloon. There should be a support force going up, gravity going down, friction force ...
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0answers
22 views

How are Newton's Laws of motion related to the amount of work exhibited by the balloon vehicle? [on hold]

A long string is running through a straw with a balloon taped onto the straw, and a penny taped onto the balloon.
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0answers
31 views

Mach's principle in empty universe, centripetal force and violation of Newton's laws of motion [on hold]

Questions about Mach's principle and empty universe has been asked many times but nowhere can I find it's cross examination with centripetal force. From my point of view the simple logic of ...
1
vote
1answer
45 views

What is the point of this type of graph? (Projectile) [on hold]

What is the point of graphing $\sin\theta \cos\theta$ vs range, during an experiment related to projectile motion? What is it supposed to tell us? Is there a website were I can acquire further ...
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1answer
30 views

Will the particle reach other end?

I place a container at rest in vaccum and filled it with air (STP conditions). Suppose a moving particle(sphere of dia 2mm) is placed at one end of the container without disturbing anything, will ...
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2answers
55 views

Will a person experience micro or zero gravity inside an aeroplane in free fall

Let us say that a person is inside a stationary aeroplane being held by a stationary helicopter in the sky. Now, the cable which supports the aeroplane breaks. Thus the aeroplane is now not bound by ...
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1answer
21 views

How to find amplitude?

What are the general methods of finding amplitude in various cases of simple harmonic motion containing spring block system? I always try with the basic sine formula of SHM to find amplitude.
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3answers
71 views

Variable mass dynamics: Particle and Rigid Body

I'm encountering some issues in the understanding of some basic concepts about the dynamics of variable-mass particles and rigid bodies. For what I found, for example reading On the use and abuse of ...
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0answers
13 views

What is the minimum velocity an object needs to hit a vertical hanging rod with, so it it can make a revolution? [on hold]

The Rod is handing vertically, Attached to a firm end. An object of mass m hits it with velocity v, so what minimum value does v should have so this rod can rotate about its pivot?
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1answer
28 views

What is the radius of the circular orbit? [on hold]

Find the radius of the circular orbit of a satellite moving with an angular speed equal to the angular speed of Earth's rotation. I started with the relation of time period ad the radius.
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votes
1answer
33 views

Conservation of momentum 1-D problem: track is not level

This problem is a standard kind of 1-D problem. You have 2 equal carts approaching each other and collide on linear air track. BUT the person setting up the track did NOT do a good job at making the ...
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0answers
27 views

What is the true weight in the geostationary satellite? [on hold]

What is the true weight of an object in a geostationary satellite that weighed exactly 10.0N at the north pole? I did: At north pole the weight of the body is 10 N. Therefore the mass of the body is ...
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0answers
31 views

kronecker product of representations on SU(2) group [on hold]

We know that if we have two irreducible representations, their product is in general reducible : $$T^{\mu}\otimes T^{\nu}(g)=\oplus \sum_{\lambda}c_{\lambda}T^{\lambda} (g)$$ where $c_{\lambda}$ is ...
2
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1answer
63 views

Can we measure kenetic energy on an absolute scale, or does it have to be measured with reference to something else?

I recently read the question Kinetic energy of an object at rest where it was suggested that the kinetic energy of an object on Earth is measured in the reference frame of Earth. Can we measure ...
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1answer
23 views

Will a heavier or lighter tank shell / bullet/ etc. travel further given the same starting energy?

Let's say I have for example two tank shells, both being the same size and having the same shape. Let's say the starting energy is 100kg*m/s^2, and the one shell is 1kg, the other 25kg. 1kg * ...
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2answers
22 views

Damping Constant for a Ball Rolling in a Bowl

How would you find the damping constant of a ball rolling without slipping in half of a sphere? I know how to find the period of the oscillation, but how would I find the damping constant ...
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0answers
9 views

Parabolic motion exercise [on hold]

From the top of a building, when t=0, a ball is thrown with a speed of 50m/s, forming a 30° angle over the horizontal. The ball hits the street, wuth a 40° angle below the horizontal. Find: a) Time in ...
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4answers
41 views

Car driving / falling off of a cliff - will it land upright?

In a recent episode of The Walking Dead, a van was pushed off of a bridge and flipped once and landed upright, on all four wheels. Assumption: the ground and cliff are both flat. Will a vehicle ...
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2answers
1k views

Kinetic energy of an object at rest

Why don't we consider that an object on Earth has kinetic energy as it is also moving at the rotating speed of Earth?
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0answers
19 views

Relative acceleration: frame of references

There is a question I've been struggling with, and I ask for your help to understand it fully. Q: An inclined plane, fixed to the inside of an elevvator, makes a 32 degrees angle with the floor. A ...
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1answer
15 views

Maximum velocity on Unbanked roads and why should friction be more than centripetal force? [on hold]

Why is maximum velocity on unbanked circular road given by $\sqrt{urg}$ where $u$ is coefficient of friction, $r$ is radius of circular track and $g$ is acceleration due to gravity? Why should ...
2
votes
1answer
39 views

Coupled ODEs that model a quad rotor

I am working on modeling the vibrations of a quad rotor. The arms that support the rotors are fixed to a center plate; that is, it is pretty much a cantilever beam with an end load. Since this is the ...
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0answers
26 views

Centrifugal force on a space station - how many RPM? [on hold]

What is the RPM needed to have 1G simulated gravity on a cylindrical space station that is 1000 meters in diameter? What is the equation to calculate that? [edit] I know that in this case it's the ...
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0answers
29 views

Angle of throwing a ball in a train moving in an arc [on hold]

Suppose a man is standing in the middle of a train car, when the train is riding with speed $V_T$ on a track section with circular curvature of radius $R$. The man wants to throw a ball with velocity ...
0
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1answer
26 views

Liquid placed in a rotating cylinder

The Question A closed vertical cylinder is filled with an incompressible liquid of mass m completely. The cylinder is now sealed from all sides and rotated about ...
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0answers
27 views

Calculating the moment of inertia in bifilar pendulums

I'm an A2 student, and I've been looking into how experimental and theoretical determined mass moments of inertia differ. I came across a method (search Youtube for Measuring Mass Moment of Inertia - ...
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0answers
8 views

How does live load versus dead load effect roof slip-resistance testing?

I have tested a wide variety of roofing materials for slip resistance in a range of roof slopes using various boot outsole materials. With all test protocols, equipment, and conditions being equal, ...
2
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0answers
18 views

Question about massive spring and SHM [on hold]

A mass $M$ is resting on the end of a spring with constant $K$. The mass of the spring is $m$, and the displacement of each element of the spring is proportional to the distance from the fixed end ...
0
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0answers
15 views

Sliding Atwood? Moving Stoplight? [on hold]

This version of an Atwood machine has two posts, separated by a known distance, with pulleys at the top. Running over the pulleys is a string of known length with three different masses: one on an ...
2
votes
2answers
117 views

What motion can emerge in a still universe? [duplicate]

I consider a very large non homogeneous cloud of dust in isolation. No external gravitational interactions. It is initially completely still and start collapsing under the its own gravity. Can the ...
4
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2answers
47 views

Friction Between Liquid and Solid Surface

How does friction between liquid surface and solid surface differ from viscosity, the friction between liquid and liquid surfaces? Also has a word describing the process been invented or is ...
2
votes
2answers
91 views

Velocity of car down an Inclined Plane

I was learning to make a car game and came across this situation where my car is on an inclined plane. It's initial velocity is 0. Now, the problem is that my memory serves me this formula to ...
0
votes
1answer
24 views

Where is the direction of kinetic friction in this question?

Suppose there is on object of 20.0kg sliding to the right. A person exert a force of 30N left on the object. The object has an acceleration of 2.5m/s^2 left. What is the magnitude and direction of ...
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0answers
8 views

Relating Angles in Elliptical Orbit

I've been trying to model the orbit of a comet of arbitrary mass around our sun from having a known initial condition with $r_0, v_0$ with angle $\alpha$ at $t_0$ around our sun. I've been able to ...
0
votes
0answers
38 views

Is it possible to use just a single equation of conservation of energy for box dropped onto the conveyor belt? [on hold]

A conveyor belt moves at a constant speed $v_0$ driven by a motor. A box of mass $m$ is dropped gently onto the conveyor belt from a relative short altitude (such that its vertical velocity is zero). ...
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0answers
36 views

Rolling without slipping [on hold]

A uniform, solid cylinder of mass $m$ and radius $r$ rolls without slipping down a plane, inclined at an angle $θ$ to the horizontal. You may assume, without proof, that the moment of inertia of ...
2
votes
1answer
41 views

Rate of acceleration for two hanging masses in two experiments

I conducted an experiment where two masses of different weight were attached by a string and fed through a pulley. The difference between the masses was $0.025\: \mathrm{kg}$. The lighter mass was ...
19
votes
9answers
2k views

Physical meaning of the angular momentum

Still reading Classical Mechanics by Goldstein, I'm struggling on a very basic notion: angular momentum. I physically understand it as the momentum of an object rotating around something given a ...
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0answers
12 views

Restoring force surface method for nonlinear system identification

I am working on nonlinear system parameters identification using the restoring force surface method (or the force-state mapping method). I found some references in which the method is explained but I ...
0
votes
2answers
57 views

Problem in Euler-Lagrange imply Newton

I'm self-studying Mechanics and I have a little problem: We can see that in Landau's book or in Wikipedia that when we inject the lagrangian in Euler Lagrange equation the term $\frac{\partial ...
0
votes
1answer
41 views

Natural frequencies of a torsion system

Find the angular displacement $\theta_1(t)$ and $\theta_2(t)$ of the system shown in figure below for the initial conditions $\theta_1(0)$, $\theta_2(0)$, and $\dot{\theta}_1(0) = \dot{\theta}_2(0) ...
0
votes
1answer
25 views

Newton's gravity formulas for ellipses

A few times I've come across formulas, which are identical for circular and elliptical orbits, except that for the second ones you substitute $r$ with $a$, where $r$ is the radius of a circular orbit ...
1
vote
1answer
45 views

Is change in kinetic energy invariant?

Consider the inelastic collision between two bodies. This question follows on from this: Is the coefficient of restitution frame independent and energy conservation?. One of the answers to this ...
1
vote
1answer
35 views

How efficient is a piston? [closed]

How efficient is a piston in converting linear motion into rotational motion? Is there a better machine which performs the same task?
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2answers
60 views

Who plays the role of centrifugal force in an inertial frame of reference?

It is noteworthy to quote a sentence from my book, It is a misconception among the beginners that centrifugal force acts on a particle in order to make the particle go on a circle. Centrifugal ...
0
votes
1answer
25 views

Q&A: What is the inertia tensor of a hexadron/hexagon extrusion? [closed]

I looked around for a long time for the inertia tensor of an extruded hexagon, and thought after a while that I would probably have already solved it by then. I don't want anyone to reinvent the wheel ...
0
votes
2answers
154 views

Why do you have less control over a bicycle with a broader steer?

I recently had an argument with someone on why a bicycle with a broader steer gives you more control. We both had different answers to this question and neither could convince the other. First a ...