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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What makes us twist in a somersault?

In a backwards straight somersault you can decide whether you twist early or late. Twisting early means, that you induce the twisting movement before you rotatation hits 180° and twisting late means, ...
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2answers
57 views

Intitutive meaning the unit of Force $N$

I infer 1 Newton of force = 1 kg.m/ sec squared means a force if acting continuosly on a body at rest would make it gain an acceleration of 1 m/sec squared each second.So the change in velocity is 1-0 ...
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1answer
60 views

Can forces in N be thought of as a length? [closed]

A solid uniform 45.0 kg ball of diameter 32.0 cm is supported against a vertical friction-less wall using a thin 30 cm wire of negligible mass. (a)make a free body diagram for the ball and use it to ...
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2answers
76 views

Why are force, momentum, and kinetic energy derivatives of each other [closed]

Force $ma$ is the rate of change of momentum, or the derivative of momentum with respect to time $$\frac{d}{dt} mv = ma = F$$. Kinetic energy is the integral of momentum with respect to velocity: ...
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3answers
1k views

In general, why do smaller guns have more felt recoil?

Why is recoil easier to control on a more massive gun compared to a smaller gun with the same bullet. Presumably the bullet leaves both guns with the same momentum, but the larger gun seems easier to ...
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1answer
60 views

Can mass-less spring system be solved?

Suppose we have typical chain of strings with masses, attached to the walls (W) at each side W-----m-----m--------W x=0 x=6 x=12 x=21 So if we let ...
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2answers
48 views

When is work done on or by something?

An example, here what my textbook says: When charges are released In electric fields charges experience the force causing them to accelerate along electric field vectors. Positive charges ...
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0answers
25 views

Whether the horizontal momentum vanishes when a rope sliping from a desk?

I meet this question in Thornton and Marion's Classical Dynamics of Partical and Systems, 5th ed, chapter 7: An extremely limber rope of uniform mass density, mass $m$ and total length $b$ lies on ...
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3answers
57 views

Reaction Force on String Wrapped Around Circular Peg

A massless inextensible string is wrapped around a frictionless circular peg. The string is taut, with tension $T_2$ and $T_1$ at the points where it leaves of the pg as shown. The segment wrapped ...
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3answers
125 views

Isn't a physical frame of reference useless for calculating speed? [closed]

Please ignore relativistic effects and the effects of the expansion of space-time due to the expanding universe theory for the purposes of this question. Whenever someone asks what is the speed of X, ...
0
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1answer
46 views

What is force of static and kinetic friction? [closed]

While I am asking more than one question in this thread they are all small concept tests that you can answer with a yes or no, and is all related to me understanding kinetic and static friction. ...
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5answers
88 views

What happens to the kinetic energy of a dropped ball when it comes to rest on the ground?

If we want to drop a ball from a height, we calculated that potential energy at bottom is zero and we say it is converted into kinetic energy. At that movement, if it is a kind of sand, we find it ...
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2answers
67 views

Tension in a massless string as it bends around a concave shape

I understand that tension in a massless string must be the same throughout when the string is straight, to prevent any section of it from accelerating at an infinite rate. However, I fail to see how ...
0
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1answer
44 views

When will a ball running between two downwards slopes stop going back and forth?

Two angles $a$ and $b$ meet at a point, making an angle $c$ between them. $a$ and $b$ are all $0 < \theta < π/2$. $c$ is $π/2 < \theta < π$ $a$ is to the left and opens to the left, $b$ ...
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3answers
65 views

Degrees of freedom of a two particle rigid system

We have two particles and the distance between them is fixed, let's suppose we know the coordinates of one particle (2,1) and other particle (x,2). So using distance formula (let's suppose the fixed ...
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2answers
28 views

What happens to a radioactive element or isotope's electrons when it undergoes alpha decay? [duplicate]

It seems to make sense that when an atom loses two protons, it would lose two electrons as well, but I don't actually know what happens.
3
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1answer
167 views

How does the Pluto-Charon orbital 'dance' affect Pluto's elliptical orbit around the Sun?

Like many Scientists (and people in general), I have been watching the New Horizons mission results with great interest. One aspect in particular caught my attention - the Pluto-Charon orbital ...
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2answers
85 views

Spring balance: what will be the reading? [duplicate]

There are two cases: When the two forces say L (for left) and R (for right) are equal. F=L=R What will be the reading? I know the reading would be F but why? When the two forces are unequal that ...
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3answers
76 views

A block sliding down a ramp lab (with friction), I keep getting a higher final energy than initial

A block of 55 g is sliding down a ramp of 35 degrees of inclination. The hypotenuse of the ramp is 63 cm and the height is 36 cm. vi = 0 as the block starts at rest. I did 3 trials of letting the ...
4
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1answer
59 views

Finding minimum time to raise a bucket

First of all, I wonder: in $F=ma$ does the acceleration have to be constant? I believe so but, just as confirmation. Problem: A 4.80 kg bucket of water is accelerated upward by a cord of ...
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6answers
1k views

Why is friction force negative in ice skater problem?

A 68.5 kg skater moving initially at 2.40m/s on rough horizontal ice comes to rest uniformly in 3.52s due to friction from the ice. What force does friction exert on the skater? I am not really ...
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2answers
89 views

how is this kind of rolling motion possible?

I was solving this problem : Suppose you put a sphere in a rough ground with velocity of center of mass $v_{cm}= v_o$ in the positive $x$ axis and with anticlockwise angular momentum $\omega_o$ so ...
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2answers
39 views

What is the work done?

A painter uses 1.93kJ of mechanical energy to pull on the rope and lift a 20kg paint barrel at constant speed to a height of 7.5m above the ground. How much work was done lifting the paint barrel? ...
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2answers
89 views

How to solve this pendulum problem using kinematics, not the principles of conservation of energy?

I have this question, because typically problems that can be solve using conservation of energy or just energy-related principles, can usually be solved sing kinematic equations. (At least is what I ...
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3answers
53 views

Is work-kinetic energy theorem useless?

This is how my book explains it: $W_{net} = \delta K$ Since the net work is tied to changes in kinetic energy and changes in speed, a mass must accelerate in order for net work to be nonzero. ...
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4answers
152 views

What exactly is work?

What exactly is work? My book confuses me: a force can lift an object to a height h, or it can accelerate an object through gravity. In all these cases, a force displaces an object and change the ...
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3answers
94 views

Trajectory of rolling billiard ball after collision with another billiard ball with same mass

So, according to this article http://www.real-world-physics-problems.com/physics-of-billiards.html , the trajectory of white (cue) ball is always perpendicular to the line connecting center of ball ...
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3answers
77 views

Is there a general rule for determining the direction of tension force?

Tension, for me, is a tricky thing. After finishing a related chapter of my book and watching a video, I still can't get a hang of it. Here is a situation: My knowledge is that tension, just like ...
2
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1answer
43 views

Why not include the energy exerted by the pitcher in a kinematics problem of a flying baseball?

I solved the question below using the principle of conservation of energy. Namely, i calculated that $$\text{KE}(i)+ (\text{Friction} \times \text{Displacment})(\cos 180) = \text{KE}(f) \, .$$ I found ...
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1answer
56 views

Work done by friction on a ball flying through air [closed]

A baseball of mass 145 g leaves a pitcher’s hand at 150km/hr, but due to constant air resistance, it arrives at home plate 20.0m away traveling at 145km/hr Assume that the magnitude of the ball’s ...
7
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3answers
198 views

Can all the theorems of classical mechanics be deduced from Newton's laws?

As above, is the whole edifice of Newtonian mechanics built upon Newton's three laws of motion? Can I deduce all the theorems without referring to further assumptions?
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How does Foucault's pendulum work in a place other than the poles?

I find it easy to understand how Foucault's pendulum works at the poles, the pendulum oscillates in a fixed plane and we, along with the earth, rotate around it. So it appears that the pendulum's ...
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3answers
62 views

Force to deflect ball colliding with wall

Suppose I have a ball with a certain coefficient of restitution. The wall can be considered indeformable and with infinite mass. Everything's in 3 dimensions, and the ball can hit the wall at any ...
0
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1answer
33 views

Force when a ring is sliding down

A setup comprises of a metal box with a metal pole at the centre. The mass of the metal box and pole is M. A ring of mass m slides down the pole with an acceleration a. The frictional force between ...
0
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1answer
32 views

What velocity do I need to get the moons orbit perfectly aligned with the earths center [closed]

I have a simulation for universal gravity with two objects. How can I calculate the velocity or instantaneous force I would need to apply to object 2 (the moon) to get it to orbit so that the origin ...
3
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2answers
124 views

Pulley-rope tension question

I'm learning mechanics and I don't understand the following (simple, I guess) concept. Here's a pulley-rope system: The force of tension, as I understand it, is defined as the force exerted on an ...
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1answer
40 views

Would I be able to see light coming towards me before it got to me

If I were in space looking at a star that just started producing light that was two light years away. Would I be able to see the light coming towards me?
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0answers
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Variable Mass System of Greater-Than One Dimension

It seems I can only find information on variable mass systems in one dimension when approached with Newtonian mechanics. When dealing with a variable mass system of two dimensions (for example), you'd ...
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0answers
19 views

I need a good book for learning mechanics in non-inertial frames [duplicate]

I'm studying classical mechanics, but without those stuffs Lagrangians and Hamiltonian mechanics...just Newtonian..the problem is a find hard to learn this non-inertial frames system, like ...
1
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2answers
56 views

Saturn V horizontally attached to Earth

If the Saturn V rocket were attached to the ground facing in the opposite direction of the Earth's spin, would it in anyway slow the Earth's spin on its axis? How significant of an impact would it ...
0
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1answer
42 views

One person catch? [closed]

Starting from rest, a child throws a ball of mass m with an initial speed v , at an angle B with the horizontal direction. The child then chases after the ball, accelerating at a constant ...
0
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3answers
72 views

How to apply Newton's first law to moving object?

I'm new to many forces, such as gravity and friction, and I don't really know how they work. I'm trying to simulate a ball bouncing with a program, and it travels at a constant speed horizontally. I ...
5
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2answers
311 views

How does one write Newtons 2nd Law using the language of forms?

Newton's second law says that $F=ma$. Supposing that the force is conservative and can thus be expressed in terms of a potential $V$ we have that $F=-dV$. We have that $V$, being a function, can ...
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0answers
13 views

Averaging Multiple Load Graph Values

I'm aware this is a problem of statistical analysis, but given my background in physics and the physical nature of the problem I felt it was best to ask this question in this SE rather than ...
0
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1answer
39 views

Net work done by projectiles?

When the projectile is in motion what is the net work done on projectiles? What i think? 0 first view: We know when we throw projectiles the initial KE and final KE is 0. So from work energy ...
0
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1answer
76 views

How do spacecraft gain kinetic energy by passing near planets? [duplicate]

When a a spacecraft like Voyager travels close to Jupiter, it somehow gains kinetic energy. I'm not sure how this energy isn't simply lost again as it moves away from Jupiter. I'm also hoping this ...
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2answers
76 views

A confusion regarding friction

Suppose there is a block which is being pulled by two forces A,B in opposite direction(as shown in figure). If we have no information regarding the forces $A$ and $B$, can we tell whether there is any ...
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3answers
74 views

How does The work done in going around any path in a gravitational field is zero implies conservation of energy?

In The Feynman Lectures, Feynman states: The work done in going around any path in a gravitational field is zero. This is a very remarkable result. It tells us something we did not previously ...
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1answer
32 views

Applying impulse to velocity

I'm writing physics engine and so far got some good results but stuck on 1 task i would like to ask. Got some mistake in my formula. Here is a question:Imagine 1 square colliding into another one. ...