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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Example of Torque, Center of Precession

So here's the set up, we have a fence of length $2L$, and a support strut a distance $l$ from the axis (think of a railroad crossing gate). We need to find the best position for the support rod, so ...
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125 views

Velocity vector for constant acceleration in newtonian mechanics

If the acceleration vector of an object remains constant, is there no change in the direction of the velocity vector? The question applies to any movements in classical physics.
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86 views

Components of forces?

Let's say we have an object lying on a slope, the weight of the object can be divided into two components one horizontal and one vertical. My question is does the weight act only in these two ...
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246 views

Centrifugal force acting on ring [closed]

Take for example the case of a rod rotating about an axis passing through its centre of mass and perpendicular to it. It has a ring hung from one of its sides. The rotation of the rod causes the ring ...
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1answer
74 views

Bullet: Piercing vs. Deflection

I am trying to create a simulation where a projectile (imagine a bullet) is fired at a surface of some kind. When it collides with the surface, I need to figure out what happens between the bullet and ...
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262 views

Simple pendulum. quick question [closed]

I was trying to find an equation to find $T$ and $\omega$ for a simple pendulum when in an elevator while the elevator is accelerating. One scenario is when it accelerates in the positive up ...
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495 views

Will larger balls make a Newton's cradle swing more stable?

I got a rather small Netwon's cradle and when I start it, the effect is not very good since all the balls start to swing where the effect we want is obvious. The balls are small and I wonder if larger ...
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159 views

Newton's second law - infinite velocity?

Given the equation $$F_{\text{net}} = ma$$ Does this not imply that if the net force on a certain object is positive, its acceleration will also be positive, and theoretically this object would ...
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355 views

Will a free-falling rod (without drag) rotate?

When we consider a bicycle is turning on a flat plane, we know that there is friction, which provide centripetal force on the bicycle. And we know that the bicycle is no longer perpendicular to the ...
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Constant Velocity 'Force'?

According to Newtons second law: F = ma, if acceleration is zero then the force must be zero, but assuming you have an object moving with a constant velocity of say 2 m/s, and that object strikes you, ...
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270 views

Moment of inertia around two axes

In the this chapter of an online pdf we are given an equation for the deflection of a beam: $$\frac{d^2y}{dx^2}=\frac{\overline{M}}{E I}$$ where $E$ is the modulus of elasticity, $\overline{M}$ is the ...
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164 views

Forces on a helical screw?

The common screws which we use, are right handed helices, the simplest parametric equations of which are:- $$x(s)=\cos(s),y(s)=\sin(s),z(s)=s$$, with $z$-axis as the axis of the helix. My question ...
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2k views

Does a force do work on an object with constant velocity?

I know that a force does no work on an object if the object's displacement is zero, but if an object is moving at a constant velocity $\bar{v}$, and a force $\bar f$ (let's say that $\bar f$ and $\bar ...
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2k views

Cylinder rolling down slope problem [closed]

A uniform cylinder of mass $m$ and radius $r$ is rolling down a slope of inclination $\theta$. The cylinder rolls without slipping. You may take the acceleration due to gravity to be $g$. At what rate ...
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996 views

Does rate of acceleration affect the amount of energy used to accelerate?

Assume you start with a car at rest. Then you accelerate the car to 100 kilometers per hour. In terms of the energy needed, does it matter how fast you accelerated the car? In other words, do you ...
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I'm having trouble wrapping my head around force, and thus acceleration, diminishing with a higher velocity when using a constant power

Here is an hypothetical situation I thought about that I don't understand. Let's say I have 2 identical rockets with a fixed power. These rockets start to race in the same direction using the full ...
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1answer
267 views

Conservation of angular momentum

We were learning about angular momentum in class today, and although it sort of makes sense, it's much harder for me to think about than linear momentum. So from what I can tell: Angular momentum ...
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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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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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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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69 views

Asking the vector form of the equation about velocity

In the undergraduate text of physics, the equation for velocity and displacement at constant acceleration are given in scalar form. For example, my text reads $$v^2 = v_0^2 + 2a(x-x_0)$$ But today, ...
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277 views

A rock connected to one end of string in circular motion gets released.. and what happens?

I know this is a basic question, but question: A rock is connected to one end of string and is in circular motion with the center being the other end of the string. Now the string gets released at ...
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Is the newton's second law for a body experiencing a frictional force, relative to the surface in contact?

Let us consider a routine mechanics problem.A block of $ 10kg $ rests on another block of $ 2kg $ on a frictionless table.Let $ \mu = 0.2 $ be the coefficient of friction(let's neglect the difference ...
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1k views

Gentle slope vs steep slope

Take for example a slide of 3m tall. Would an object (starting from rest) sliding down a gentle slope have a lower speed than a steep slope? (Note: Height of slide is the same,disregard friction.) ...
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310 views

Centripetal acceleration for particle that moves in a circle at non-constant speed

How is $a_{R}=v_T^{2}/r$ derived for changing tangential speed? ($a_R$-centripetal component $r$-distance from axis $v_T$- tangential speed)
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Free body diagram of rod in sphere

I was finding the free body diagram part of dynamics quite easy until I found this question , Here's how it goes : A rod AB is placed inside a spherical shell, whose inside surface is rough. Draw ...
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997 views

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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193 views

How to work out momentum when there are velocity and mass changes

I have a pretty simple homework question, but I can't rap my head around it. In the question a swimmer of $55 \mbox{ } \mathrm{kg}$, jumps off a stationary raft of $210\mbox{ }\mathrm{kg} $. The ...
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95 views

Conservation of momentum

I've got following problem. There are $N$ particles in an isolated system. The equation of motion for a particle $i$ is ...
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186 views

Initial velocity of an orbiting object that lands on the planet with zero speed w.r.t the surface

How would you determine what initial velocity $v(r)$ of an object would have to be at some arbitrary point in the vicinity of a planet such that the object will end up on the surface of the planet ...
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2k views

What force does bathroom scale measure?

When you stand on a bathroom scale, I know that the force displayed is the normal force. Since it is the normal force, then technically the force displayed would actually be Fg= (mass)(acceleration) ...
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Relation between work, kinetic energy and potential energy

We derived two equations in class. The work done between two points $A$, $B$ is equal to the difference between the kinetic energy at the last point and the one at the first point. The work done ...
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Is there a relation between the magnetic field force of the earth and the gravitational force between the earth and other bodies?

According to Newton's Universal Law of gravitation, we can say that a huge body of mass will attract another body of mass within a short range, however, if both bodies are for instance magnetic, ...
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Tension in a massless string around a pulley [closed]

A pulley having some mass has a massless string around it, with two unequal masses at the end of the string. Sufficient friction is present between pulley and the string such that the string does not ...
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1answer
198 views

Solving differential Equation for the Two-Body Problem

So, I'm following the derivation in D. Morin, Introduction to Classical Mechanics, of the equations for a two-body system. I understand all of it, aside from this one step. When he's talking about ...
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117 views

Constant of gravity in earth fixed coordinate system

I have this problem: If the constant of gravity is measured to be $g_0$ in an earth fixed coordinate system, what is the difference $g-g_0$ where $g$ is the real constant of gravity as ...
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553 views

Simple conservation of momentum and frame of reference problem

I'm making a very simple physics engine based on momentum, and I'm solving what response to use for a collision from each involved object's frame of reference. However, something about how I'm ...
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740 views

Time period for spring connected body

Two identical springs with spring constant $k$ are connected to identical masses of mass $M$, as shown in the figures above. The ratio of the period for the springs connected in parallel (Figure 1) ...
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173 views

Will a helicoper which is hovering inside a closed box move with the box when we move it? [duplicate]

I got this micro helicopter to play with, you know that cheap double bladed ones you can find for $25 or so. Anyway last night I was on bed trying to sleep and I got this idea, what if we put the ...
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169 views

Escape velocity to intersection of two gravitational fields

Find the minimal velocity needed for a meteorite of mass $m$ to get to earth from the moon. Hint: the distance between the center of earth and the center of moon is $\approx 60 R_E$, and the ...
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301 views

Change in speed of a satellite

Suppose there's some satellite orbiting the earth in circular motion. Suppose there's an asteroid that hits the satellite in the same direction as the instant velocity vector of the satellite. The ...
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204 views

How to calculate time for ball to reach plane while considering mass, gravity and wind resistance?

The scenario that I'm having is such that a ball of radius $15mm$ is thrown from a location point $\vec{p}=(2, 5, 2)$ in a direction of $\vec{d}=(3, 0, 4)$. The initial velocity is $30m/s$. There were ...
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286 views

Wedge and Sphere problem

A sphere of radius $R$ is in contact with a wedge. The point of contact is $\frac{R}{5}$ from the ground as shown in figure. Wedge is moving with velocity $20~\text{m/s}$ towards left then the ...
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1answer
3k views

How do you find (initial) velocity using conservation of energy?

Without mass; only time, distance, and height is given. For example: For this lab, the reference level was 100cm above ground therefore the height of the object was 10cm. I determined time and ...
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1answer
107 views

What Speed Would an object need to leave the earth at to reach L1? [closed]

Let's say the Earth is an airless sphere. What speed would an object weighing 1 kg need to leave the surface at in order to get to and be motionless at L1, where the Moon's gravity becomes stronger ...
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1answer
107 views

energy of deflection of a moving object

Imagine an object moving in a straight line in space, perhaps shaped like a yo-yo (to make rotational effects negligible). Suddenly a constant force is exerted at right angles to the direction of ...
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2answers
192 views

When I ride my bike, does half of the energy go into the earth?

When I ride my bike, does half of the energy go into the earth because of Newton's third law? Does the energy in the earth transfer into heat upon my brakes when I utilize them? If the earth was 2000 ...
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Finding maximum speed in a work-energy problem

I have the following problem: The Royal Gorge bridge over the Arkansas River is $310\text{ m}$ above the river. A $57\text{ kg}$ bungee jumper has an elastic cord with an unstressed length of ...
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429 views

Lagrange-Euler equations for a bead moving on a ring

A bead with mass $m$ is free to glide on a ring that rotates about an axis with constant angular velocity. Form the Lagrange-Euler equations for the movement of the bead. Solution: Let us ...
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734 views

Calculating vertical velocity component of a particle with mass, given the hit point of parabolic motion

Consider the following situation: I have a particle with a given mass that at a given instant of time (let's say $t_{0}$) is placed at the system origin. The particle has a constant velocity ...