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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Torque and force from friction upon a rotating 2D disc

I am developing a 2D physics engine, and therefore I got stuck with this problem: A disc (2D) is sliding over a surface. It is both rotating and translating. How will friction act upon it? What ...
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Forces acting on a body on a slope, while the slope is accelerating forward

I have the following problem: I have to determine the initial acceleration a body with mass $m$ experiences while it is on a slope and the slope is pushed forward with acceleration $a_0$ and the ...
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2answers
130 views

Deceleration rate of objects of different mass but the same otherwise

Using a tennis ball as an example object, if one ball weighs 1 ounce and the other is 2 ounces, and both are struck at 100 mph on the same trajectory, would there be any difference in the deceleration ...
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Conservation of angular momentum -Two small balls A and B, each of mass m, are joined rigidly to the ends of a light rod of length L

It is clamped at the centre in such a way that it can rotate freely about a horizontal axis through the clamp. The system is kept at rest in the horizontal position. A particle P of the same mass m is ...
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19 views

Confused about question and related concept [on hold]

Dust particles are uniformly distributed in space with a mass per unit volume 'd' . A circular plate of area A is moving in this space at velocity v. The dust particles that come into contact with ...
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72 views

Figuring out the time period of an Atwood system

SO I was working on Atwoods, when I came up with the following problem, It is more complicated but i should understand this simpler scenario first. As shown in the diagram above, (Atwood machine), ...
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1answer
24 views

A parameter to quantify instability in flight (of a housefly)

I study the flight of houseflies. I plot their body angles, as they fly in a chamber. I have two such plots. One of a normal housefly, and the other plot with one of their haltere removed. Now it is ...
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1answer
52 views

I can make the mechanical energy 0 or in fact anything. Is this normal?

We let the rope fall with $\alpha = \pi/2$ (no initial velocity). if I choose the original of potential energy as the picture indicates there, this means that: $$E_m = E_{pe} + E_c = \frac12mv^2 ...
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1answer
81 views

If reality is relative, then what about Newton's bucket argument?

There is nothing outside the universe. - Lee Smolin So, there can't be any absolute frame. Everything must be measured relative to an entity that exists in the universe. Thus, space ...
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2answers
58 views

Boy , Table and the Newton [duplicate]

Suppose a boy is trying to stand on a table. If the table can hold upto a particular force, the boy would fall on to earth. If he stands on the table and providing greater force than the table can ...
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1answer
55 views

Big jump or small jumps?

To travel a certain distance s, is it more energy efficient to use one massive jump, or several small jumps? (First approach deleted, didn't make sense) This approach is probably a lot better. ...
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2answers
128 views

Case of the mysterious bullets (taken from Mad About Physics)

"Two ideal bullets, identical in shape, size and mass, strike the same target with the same speed just before the collision. Force meters at the target register two times the force value for bullet A ...
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49 views

When a force pushes an object does the force move the object?

When a force pushes an object from a point a to a point b does this mean that necessary the force moves the object?
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1answer
35 views

Reversibility in classical mechanics

I am watching Susskind's 'Theoretical Minimum' videos. At one point in his course on classical mechanics (2nd video if I remember correctly) he affirms that Netwon's second law of motion makes ...
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3answers
90 views

What is the difference between Newton's first & third law?

Newton first law states that object stays in fixed state, unless external force is applied. Newton third law states that: if there is action then there will be opposite & equal reaction. So if ...
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23 views

How to calculate the linear and angular dampening of a solid moving in a liquid? [on hold]

I am currently making a 2D physics simulation and I have to calculate the linear and angular dampening of a composite body (represented by a force vector field). I already calculate the linear and ...
2
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1answer
80 views

Resemblance between Coriolis force and magnetic part of Lorentz force

If we interchange velocity with charge and omega that is rotation of a system with $B$, magnetic field, we get the same thing. Is there any deeper meaning to this same mathematical form?
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23 views

Transmissibility

An extract from a school maths mechanics textbook reads: To deal with cases in which the body is not rotating freely under gravity, we need to take into account also the work done by other ...
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115 views

Newton's third law of motion when moving between two surfaces

If for every action there is an equal but opposite reaction, then why doesn't a ball keep on moving when made to move between two surfaces, should elasticity of surface, gravity and friction be ...
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197 views

How to intuitively understand Newton's third Law?

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body. Newton's third ...
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451 views

Given Newton's Third Law, how can an inanimate object create a force?

Newton's Third Law states that Whenever any force is exerted by a body#1 on any other body#2, another force which is equal in magnitude and opposite in direction is exerted on body#1 by body#2. ...
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35 views

A block of mass M moving on a frictionelss horizontal surface collides with a spring of spring constant k and compresses it by length L [on hold]

A block of mass M moving on a frictionelss horizontal surface collides with a spring of spring constant k and compresses it by length L. What is the maximum momentum of the block after collision? ...
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69 views

About Kepler's Law

When Earth goes near the Sun, its velocity increases and when it goes far from the Sun its velocity decreases. Then why according to Kepler's law is the time period $T^2 \propto a^3$, where $a$ is the ...
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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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129 views

“Skidding” to Brake on a Skateboard

When people are skateboarding, sometimes they kind of push out their back foot when they turn while carving, causing the board to skid a bit. I was wondering the physics behind this, any details on ...
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Slinky base does not immediately fall due to gravity

Why does the base of this slinky not fall immediately to gravity? My guess is tension in the springs is a force > mass*gravity but even then it is dumbfounding.
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Parallel axis theorem

For this question we are working in 2-D space. Let's say that we have an arbitrary body. I know the inertia with respect to a perpendicular axis (to the body, that is) that passes through a point (A). ...
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1answer
25 views

Newton's Second law of motion: Elevator problem [on hold]

this is a question about newton's second law of motion that I am a bit stuck on. One end of the cable of an elevator is attached to the elevator car,and the other end of the cable is attached to a ...
2
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1answer
48 views

Estimate the maximum distance of water spatter

There is a faucet dripping water from height $H$ onto a smooth, horizontal ceramic surface, and I need to give a upper bound of the maximum distance between the water spatter and the point directly ...
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1answer
41 views

3 pulley and 2 masses,relation between their accelerations [on hold]

I want to find acceleration of each mass in this system. lets take length of rope between three pulleys as $L$. then we can use this relations ...
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1answer
26 views

An unwinding cable problem [on hold]

Suppose a light cable is wrapped around a solid cylinder with mass $M$ and radius $R$. The cylinder rotates with no friction about a stationary horizontal axis. The free end of the cable is attached ...
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1answer
47 views

What arguments and examples did Newton give in support of Absolute time and space?

As everyone knows, Sir Newton advocated the Absolute Space & Time theory. But what examples and arguments did he confer to establish his theory? I read the wiki page where it was written that he ...
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1answer
117 views

Rotating platform with pulleys and stacked blocks

This was a practice test question. Consider the following figure. (If the frictional coefficients are unclear, between A and B we have $k_1 = 0.3$, B and platform is $k_2 = 0.2$. If you further ...
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110 views

What are absolute space & time? Why are they not absolute in reality?

As said by A.P. French in Newtonian point of view: Space is a sort of stationary three-dimensional matrix into which one can place objects or through which objects can move without producing any ...
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19 views

Which has more chance of floating: ring or sheet of same material? [on hold]

A ring and a sheet of same material, if kept carefully in water. Which will have a better chance to float and why? Also please explain the direction of tension force.
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57 views

Mathematical misunderstanding of Work-Potential Energy Theorem?

This is a relatively basic question, but I don't understand why it is the case. This is from my dynamics book and is mainly a mathematical misunderstanding. $$ \ dU = F\cos\theta ds $$ Which means ...
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3answers
48 views

Do components of force have direction when doing work?

When we get angle > 0, the x-component of force is along the direction of displacement and so their product is called Work. So the x-component of force is said to have direction of the respective ...
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100 views

Do objects really move in the direction of the force applied?

According to the second law of motion: Direction of the force is in the direction of change in momentum. Now, I came before a problem. Though an easy one, I was perplexed at a point. A ...
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Force and Displacement: which come first? [on hold]

In nature, does force generate displacement, or displacement generate force? For instance, a spring oscillator, whenever you give a force, the displacement comes along and you will feel reaction ...
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21 views

Working with problems including friction forces [on hold]

A body of mass $0.3 kg$ is taken up an inclined plane of length $10$ and height $5 m$ and then allowed to slide down to the bottom again.The coefficient of friction between the body and the plane is ...
2
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1answer
60 views

The subtle differences between angular momentum and centrifugal force?

I am a mathematician wanting to understand the differences between the concepts of angular momentum and centrifugal force. The following two ideas are clear to me from a physical point of view, but ...
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42 views

Collisions in two dimensions: using relative velocity

I am following this tutorial which reviews some physics on collision resolution. I understand relative velocity, the mathematics is not a problem for me. However, despite my head scratching and ...
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4answers
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+200

How did Newton discover his third law of motion?

How did Newton discover his third law? Was it his original finding or was it a restatement of someone else's, like the first law coming from Galileo? What initiated the concept of what is now known as ...
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4answers
89 views

Why are we still teaching Newtonian physics if it's “false”? [duplicate]

Why are we teaching an outdated theory when the math in general relativity isn't that hard? I really don't see a reason why we should teach a highly oversimplified theory in our schools. For me, it's ...
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Can internal forces do work?

My Mechanics textbook claims that the sum of the work by internal forces is not generally zero. translated to English the paragraph reads: Notice about the work by internal forces: the work by ...
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138 views

Does a pivot exert an additional force, normal to the centripetal force, on an object rotating about it?

A thin plank of mass $M$ and length $l$ is pivoted at one end. The plank is released at 60$^{\circ}$ from the vertical. What is the magnitude and direction of the force on the pivot when the plank ...
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1answer
147 views

Rolling a ball into a cone; what should the forces overall be?

This is my solution to finding angular displacement/velocity/acceleration on cone so far. Consider a cone, with an apex of half-angle $\psi$ pointing down, and a height of $h$. If I roll a ball into ...
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1answer
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Equation of Trajectory [closed]

I was reading about Lorentz force law and motion of a charged particle under Electric field or magnetic field and I understood how they move in it. But as I was moving further I came across the ...
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Can a projectile moving at supersonic velocities leave a silhouette in whatever it hits?

I was recently reading this, and Floris's answer confirmed my knowledge that the information of an collision travels at the speed of sound. While I was thinking about that, my mind wandered and I ...