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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733 views

Friction problem having two blocks on separate inclined planes connected by a string

This is a question I found in my old high-school textbook(I'm revising the topics for a course).Two blocks A and B of masses $1kg$ and $2kg$ are placed on a fixed triangular wedge by a massless ...
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1answer
1k views

Calculate Mass based on Velocity and Acceleration

I am attempting to design a obstacle avoidance system with the Arduino. My position (for now) is going to be stationary. I will be detecting an incoming object and I want to use the below known ...
4
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2answers
553 views

Small oscillations of the double pendulum

From the Lagrangian I've got the following equations of motion for the double pendulum in 2D. (The masses are different but the lengths of the two pendula are equal.) Let $m_2$ be the lowest-hanging ...
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1answer
365 views

Why is kinetic energy only “often $1/2mv^2$”?

I am reading the first few pages of Nakahara and refreshing my memory on physics I learned a while ago as a physics math undergrad. Nakahara defines a field $F$ to be conservative if it's the gradient ...
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2answers
515 views

Does the mass of a car frame has any effect on its horsepower?

I want to know whether decreasing the mass of the frame of a car will increase its horsepower. From what I understand horsepower is a measure of the car's ability to transport load, and decreasing the ...
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1answer
222 views

Circular motion question

(Q) Find the maximum speed at which a truck can safely travel without toppling over, on a curve of radius 250m. The height of the centre of gravity of the truck above the ground is 1.5m and the ...
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2answers
2k views

How can I calculate the pressure against the sides of a container? [closed]

While answering this question on DIY.SE, I wanted to calculate the amount of pressure (in psi) that would be exerted on the walls of the container. However, I don't know much about how to calculate ...
4
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2answers
144 views

Why isn't the product rule used in the definition of mechanical work?

Mechanical power is normally defined as $P = \mathrm{d}W/\mathrm{d}t$, and work is normally defined as $W = \vec F \cdot \vec x$. Today an undergrad pointed out a confusion he had from Griffiths' ...
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1answer
231 views

Integrals of Power

This question has two parts: a question about a specific expression and a question about a family of expressions. In what follows I will omit all constants of integration. If we integrate force with ...
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2answers
1k views

Two masses connected by a string in horizontal frictionless table

Suppose that two masses with different mass are connected by a string in horizontal frictionless table. Then when there is equal acceleration for two masses, string force would extend in some ...
4
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3answers
200 views

Finding the equation of motion of anharmonic potential [closed]

If I have a potential given by: $$U=U_0\left[2\left(\frac xa\right)^2-\left(\frac xa\right)^4\right]$$ It says that at $t=0$, the particle is at the origin ($x=0$) and the velocity is positive and ...
3
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1answer
430 views

How to understand Feynman's reasoning about perpetual motion?

I'm studying Feynman's Lectures on Physics, and I'm not really understanding his reasoning here: Consider weight-lifting machines $\overline{}$ machines which have the property that they lift one ...
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1answer
875 views

Relationship between angles [closed]

Question: Find the relationship between angles $\theta$ and $\phi$ using the equations of equilibrium and solve for $\theta$. Express your equation for $\theta$ in terms of $\phi$. ...
4
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1answer
379 views

Plastic bottle floating and sinking

I was doing this experiment: i take a plastic cup, put in a container of water, it floats – then when I put a coin in the water, it sinks and rests at the bottom. So to make the cup sink, i fill it ...
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0answers
84 views

Find contact force given sphere's radii and distance

I simulate scenario of two contacting elastic spheres, where their radii and the distance of their centers is known, and repulsive force should be computed. Material parameters are also given. Most ...
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0answers
259 views

Angular Frequency about stable equilibrium

So I have the potential energy defined as: $$U(x)=U_0[2(\frac xa)^2-(\frac xa)^4]$$ And I want to find the angular frequency of oscillations about the point of stable equilibrium. I found the point ...
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2answers
1k views

Finding the period of an infinite length pendulum [closed]

What would be the period of a pendulum with an infinite length, assuming a non-rotating Earth? The answer is not infinity.
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0answers
50 views

The electron and classical dynamics

Can I use Newtonian laws of dynamics and kinematics applied to electrons (like $F = ma$ and $s = s_0 + v_0 t + at^2/2$)? If not, why not? I know that everything in principle behaves in a quantum ...
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1answer
855 views

Are principle of Conservation of energy and principle of conservation of momentum consequences of Newton's laws?

It is known that principle of Conservation of momentum and principle of conservation of energy are two fundamental principles of physics.But in RP Feynman's Lectures of physics, in the chapter of ...
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2answers
205 views

Is there a definition of force? [duplicate]

Well, Newton's three laws talks about forces, but no definition is given. In truth, Newton's second law gives an idea of what total force is: the time change rate of momentum. But, if we have a force ...
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2answers
231 views

About vector form of friction

I read a text on mechanics and in the chapter on friction, there written that the kinetic friction is in the form $$f_k = \mu_k F_N$$ where $f_k$ is the kinetic friction, $\mu_k$ is the kinetic ...
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1answer
208 views

Newton third law. Is there a limit on how much force you can apply to an object?

Recently in class we went over Newton's Third Law. In the book they put an example of hitting a punching-bag with your fist and hitting a piece of paper, or an object with much less mass. It's clear ...
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0answers
159 views

Air resistance of a general shape object

I'm trying to code a simple physics simulator in C++ but I'm stuck on the air resistance issue. Surfing the Internet I only find a drag coefficient for very basical area shapes when the air is ...
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3answers
2k views

Normal force of loop-the-loop at the side of the circle

In the loop-the-loop ride a car goes around a vertical, circular loop at a constant speed. The car has the mass of 230 kg and moves with the speed of 300 m/s. The loop-the-loop has a radius R=20 m. ...
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3answers
3k views

How does a car's low gear increase power while going slower?

People have always told me that when a car goes into low gear, it goes slower but puts "more power" or "more torque" on the wheels, which allows it to descend slippery slopes or get out of mud traps ...
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2answers
253 views

Is inertia present in a body while in state of motion?

According to Newton's law of inertia (written in book:The Mathematical Principles of Natural Philosophy**) it is said that in all objects having mass, have always inertia included in their property ...
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2answers
6k views

Simple rope tension problem

I have this really simple rope tension problem that can be solved for seconds using simple logic. I know what the answer is, I know why it is, but I cannot write it down and explain it mathematically. ...
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0answers
46 views

How to prove Newton's second law with quantum mechanics? [duplicate]

Newton's second law claims that $F=ma$. In terms of quantum mechanics, the equality can be written as $ \frac{d\langle p \rangle}{dt} = -\langle \nabla V(x) \rangle$. How can I prove this with ...
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2answers
137 views

Questions about gravitational and inertial mass [duplicate]

What differences between gravitational mass and inertial mass? I cannot tell the differences between them. In history, which concept was put forward firstly? Are there some experiments to prove ...
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1answer
401 views

Engineering Mechanics (Dynamics) Problem [closed]

Cylinder A has a constant downward speed of 1 m/s. compute the velocity of cylinder B for θ= 30 and θ= 45. The spring is in tension throughout the motion range of interest, and the pulleys are ...
5
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4answers
1k views

Explaining Newton's Laws of motion to a 6 year old

An old professor of mine once said that an effective means to get people interested in Physics is to get them started early. What would be an effective and meaningful (and fun) means to explain ...
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1answer
497 views

Conservation of momentum collision problem

The problems is as follows: A 2000kg Ford was travelling south when it collided with your 1000kg sports car travelling west. The two badly-damaged cars became entangled in the collision and ...
3
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1answer
158 views

Force on bolt holding up jet engine on plane

I am to solve the following: A jet engine of mass $m$ is fastened to the fuselage of a passenger jet by a bolt. During flight, the plane encounters turbulence, which suddenly imparts an upward ...
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3answers
789 views

How to determine direction of forces in a static problem?

I am consistently getting this wrong. To me, in the picture below, it would make sense that the structure would be pulling downward, and the cable BD would be pulling upward - thus the system is in ...
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2answers
844 views

Object with friction in circular motion caused by a string

A physics problem in my textbook reads: A 0.40kg ball, attached to the end of a horizontal cord, is rotated in a circle of radius 1.3m on a frictionless horizontal surface. If the cord will ...
5
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1answer
179 views

Is an alpha particle's curvature in a magnetic field visible with a homemade cloud chamber?

I'm trying to do some calculations to see just how strong a magnet you'd have to have, in order for curvature to be noticeable in a rudimentary cloud chamber, with lead-210 as an alpha particle ...
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0answers
56 views

Modeling of exact stick-slip-friction using Linear complementarity problems (LCP)

Within my master's thesis, I try to model a machine elements and have to model the exact slipping and exact sticking between the bodies. So I noticed that such problems can be formulated as a LCP. ...
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0answers
252 views

How to find the angle of elevation and launch speed? [closed]

A particle is projected from a point on level ground with a speed of $u$ meters per second and an angle of elevation $\theta$. The maximum height reached by the particle is $42$ meters above the ...
3
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3answers
377 views

Is a spinning object heavier than a non-spinning object?

Does spinning an object make it heavier? A real-world example: I was mowing the lawn in front of my house, a lawn that tends to have some steep inclines. I realized that the lawn-mower was easier ...
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1answer
123 views

Investigation of a pendulum's period, problem creating equation to sum the dynamic velocity

I am investigating the period of a pendulum swing. This is a simple harmonic pendulum and I am already aware of the common, but slightly inaccurate, $2\pi \sqrt{\frac{L}{G}}$ formula. My problem is ...
4
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1answer
100 views

Can it require different amounts of energy to generate the same impulse?

According to impulse principle the impulse is the same as the change in the object's momentum: $\bar I = \delta p$ Because the momentum can be calculated like this: $\bar p = m\bar v$. If we solve ...
8
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4answers
597 views

Is it correct that tires quickly get bald when used at high speed?

In my investigation, tires will quickly get bald if we ride a motorcycle at high speed. Is it correct? How to explain it in physics? Does the friction increase at high speed rotation? Update: The ...
4
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2answers
242 views

Weight registered of a falling chain

Let's say I have a metallic chain. Suppose I hold one of its tip of in my hand let the chain hang freely downward such that the other tip touches a weighing scale. At this point, with me holding the ...
3
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1answer
172 views

How does heating cause motion?

W.R.T. Newton's laws a force is required to change the state of rest of a body. Then how does heating cause a particular object's atoms and molecules to wiggle ? What is the force being applied when ...
2
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3answers
1k views

Pulley problem - unable to understand the concept

Given: The pulley is moving towards the right. All blocks have different masses. (The pulley and the strings are massless.) What I don't understand: Is the tension the same for both A and B? ...
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0answers
42 views

What is Verlinde's statistical description of gravity as an entropic force? [duplicate]

What is Verlinde's statistical description of gravity as an entropic force leads to the correct inverse square distance law of attraction between classical bodies?
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2answers
2k views

Two boxes that are connected pushed by force - what happens between two boxes?

So when two boxes are connected together, and force is applied, two boxes move with the same acceleration. (assuming force is constant.) My question is, how are forces between two boxes get cancelled ...
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3answers
197 views

Does the ceiling fan make the air and dust spiral in?

Does the rotation of ceiling fan makes air circulate in a spiral, circular motion beneath the radius of fan or the air from outside is also mixed with it and replaces the air in room? A ...
0
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2answers
246 views

Can somebody help me find the tension in this string? [closed]

My friends and I are debating over the correct answer for this particular physics problem. There's a pendulum with a $2kg.$ mass and a $5m.$ string attached to a ceiling at $53^{\circ}$ to the ...
0
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1answer
137 views

Motion in a central field and angular momentum

Is it correct that for a motion in a central force field, e.g. a gravitational field, the absolute value of the total angular momentum of the particle and the component of the perpendicular to the ...