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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A problem related to Work done by falling bodies : Expert's attention much needed!

I'm having a lot of trouble with this question, that I've found in my textbook. I've solved it in my own way and it's very simple! But the solution in the book is totally different. It doesn't make ...
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0answers
29 views

Deceleration of a space shuttle [on hold]

A space shuttle is decelerated by parachutes, which cause a deceleration of $a(v)=-0.04 v^2$. After what time is a space shuttle decelerated to $1m/s$ if it had a velocity of $50m/s$ when the ...
4
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2answers
43 views

Confusion with potential in simple pendulum

I'm a maths student taking a course in classical mechanics and I'm having some confusion with the definition of a potential. If we consider a simple pendulum then the forces acting on the end are ...
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0answers
25 views

Velocity of ball after collision [on hold]

I have a question regarding impulse. Suppose at a certain point of time ball has velocity $\mathbf{v}\cos\theta$ in horizontal direction and $\mathbf{v}\sin\theta$ in vertical direction (downwards) ...
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7answers
3k views

Throwing an object around the Earth. Is it possible?

Some of you might be familiar with the cartoon called Astérix. In one of the episodes, Obelix (the really strong fat guy in the stylish striped pants) enters a spear throwing competition. He beats the ...
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3answers
47 views

Traveling to Mars in 24 Days

I am trying to calculate an electromagnetic rail launch from the Moon but I need to know if humans can survive the launch. Please see the specs below. 150 miles of track Proposed final launch speed ...
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0answers
19 views

Men on the pully palte to lift [on hold]

A plate has a fixed pulley. A men, standing on a plate pulls up with one end of the rope to try to lift the plate and himself; the other end of the rope is over the pulley to fixed on the ceiling, ...
-2
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0answers
28 views

classical-mechanics [on hold]

If the mass of person is less than the mass of elevator, the $\mathit{N}$ will be negative. What does that mean? For instance: person mass = $30~\text{kg}$, elevator mass = $60~\text{kg}$. At ...
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1answer
26 views

A question on tangential and centripetal accelerations?

What is the proof that the component of acceleration perpendicular to motion for all motion is $v^2/r$, where r is the radius of curvature? Also, what is the proof that the component of acceleration ...
2
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1answer
16 views

Problem on bending plates in Newtonian Mechanics?

I am reading a book on interesting physics problems and demonstrations. One of the problems in the section on buildings, structures and equilibrium talks about a plate with one side attached to the ...
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1answer
15 views

Is the buoyant force on an object is the reaction force?

Is the buoyant force on an object is the reaction force for the force exerted by the objects on the fluid (newtons third law)? Or there are two sets of action reaction force? (objects force and ...
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1answer
45 views

Lagrangian mechanics and initial conditions vs boundary conditions

It bothers me that many basic books on the classical mechanics don't discuss the following difference between "Newton's laws" and the "Principle of stationary action". Newton's laws can predict the ...
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1answer
30 views

Equation for Figuring out the Displacement for a Projectile at an Angle

I'm wondering if anybody can simply tell me if there is a simple formula to solve for displacement when you've been given the launch angle and initial velocity? See; http://is.gd/LpT1EA To some, it ...
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1answer
20 views

Balancing sphere

A cube is balanced on the very top of a sphere, and is given a small push in some direction, at which point it begins sliding down that side of the cube (due to gravity). Now, I want to keep the cube ...
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0answers
10 views

dynamics: force, pulley, person in elevator [duplicate]

An 30-kg person standing on a 60-kg elevator suspended by a rope passing over a stationary pulley that is free to rotate. The other end of the rope is held by the person. The masses of the rope and ...
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0answers
27 views

In relation to what, are the orbits of planets defined? [on hold]

I was pondering geocentric orbits. And of course, a geo-stationary orbit is an orbit in which a satellite orbits at the same speed and direction as the rotation of the Earth, so that it seems from ...
4
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1answer
54 views

Uniqueness of the equivalence class of inertial frames

Let us define an inertial frame as a frame of reference where the laws of physics take their usual form, as opposed to non intertial frames where one has to introduce pseudo-forces. We can further ...
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0answers
30 views

Two cars colliding with different speeds

If I have one car travelling at 30 m/s and another travelling at 10 m/s both weighing the same amount, why is it that the car travelling 10 m/s would have more damage? According to Newton's third law ...
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1answer
15 views

Circular motion normal force

Extracted from this article (see the bottom section): Some roller-coasters have loop-the-loop sections, where you travel in a vertical circle, so that you're upside-down at the top. To do this ...
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4answers
68 views

Absolute (as opposed to relative) concept of inertial frame

In mechanics there is a relative concept of "inertial frame": frame A is inertial with respect to frame B if A moves uniformly with respect B. That concept is easy to understand. There also seems to ...
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0answers
32 views

Under what circumstances will a particle in a paraboloid oscillate harmonically around the lowest point? [on hold]

A particle of mass $m$ is moving in the gravitational field $g$. It is confined to move frictionlessly on the surface of the paraboloid $z(r,\phi):=a\cdot r^2$. Here, $a>0$ is a constant. The ...
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1answer
39 views

will frictional force work against the vertical direction of velocity of an object?

We assume that an object is placed on a horizontal plane. If this object is accelerated to vertical direction, will frictional force act against the vertical direction of velocity of object? For any ...
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3answers
60 views

Is the work-energy theorem valid for only particles or rigid bodies as well?

Is the work-energy theorem valid for only particles or rigid bodies as well? Most places where I have read this seem to claim the latter. But an example I thought up has been troubling me. Consider ...
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5answers
1k views

If the solar system is a non-inertial frame, why can Newton's Laws predict motion?

Since there is no object in the universe that doesn't move, and the solar system likely accelerates through space, how did Newton's Laws work so well? Didn't he assume that the sun is the ...
2
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1answer
193 views

Is force the derivative of energy?

In my lecture today my professor briefly mentioned that force is the derivative of energy but I did not really get what he meant by that. I tried to express it mathematically: ...
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1answer
15 views

Pure Rolling from a stationary surface onto a moving surface

Suppose a sphere rolls without slipping on horizontal stationary ground. Now, suppose the sphere rolls onto a surface which is moving at some velocity with respect to the previous stationary ground. ...
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2answers
38 views

What is the use of orthogonal curvilinear co-ordinate system?

Orthogonal curvilinear coordinate system is made of intersecting sets of confocal ellipses & hyperbolas. But, I have found no book that would describe this how to use this coordinate system ...
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0answers
29 views

Vector Physics Line Point Collision [on hold]

Question: What laws should I use to distribute the net velocity where: A Ball collides with a rope that always stays at high tension with two Balls on both sides which have arbitrary velocities. ...
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2answers
35 views

Can center of mass move without any force?

For instance, consider a weight on one end of the ring. Assume that the ring has negligible mass compared to the weight. When the weight splits into two, moves around the ring and recombines at the ...
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2answers
62 views

An interesting problem on springs [on hold]

If I place two identical objects of mass $m$ at either end of a spring with spring constant $k$ and the whole system is placed on a horizontal frictionless surface, then what is the frequency of ...
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1answer
33 views

Very confused about effective spring constant

I know that for springs in parallel, the effective spring constant is $k_1+k_2$ and for springs in series the constant is $1/(1/k_1+1/k_2)$. But there are some weird problems where finding the ...
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1answer
36 views

Tipping over objects on a frictionless surface

Is there any way you can topple over a rod which is standing up on a frictionless surface?
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1answer
50 views

Where does energy goes if I jump down from a balloon?

Suppose you are in a hot air balloon of mass $M$ which is floating in the air, and you get out and start climbing down a rope at constant velocity $v$. By conservation of momentum we can show that the ...
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2answers
37 views

Linear Gravity Inside Solid Sphere Derivation

I am currently taking a dynamics module at university and am revising for a midterm exam. One of the problems on a past paper was to consider a mass falling through a hole in the Earth (pole to ...
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3answers
58 views

How to explain that an object at a certain point with zero velocity can move away from that point by having an acceleration?

As A.P.French points out: You may feel, . . . , that we have gone to excessive lengths in our discussion of instantaneous velocity & acceleration. But make no mistake about it; these are very ...
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0answers
36 views

Clearing up confusion about orbital mechanics

When I see an orbital mechanics problem, I recall the following things from my "toolbox": Angular momentum is conserved for a body orbiting a planet, since the torque due to gravity is 0. Kinetic ...
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1answer
52 views

Springs at an angle [on hold]

I'm trying to find the equation of motion for the following system: This is how I proceeded: Let's call the length of the hypotenuse $s$. Then, $$F = 2 \sin{\theta}\cdot-k(s - l_o) = -2kx ...
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1answer
28 views

If a place a spring in a box and drop the box, what happens?

Suppose I a holding a box in my hands, and inside the box a spring with some mass attached hangs from the cieling of the box. Initial the system is at equilibrium, then I let go of the box and it ...
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1answer
25 views

Placing an object in a tub changes the weight of the tub?

Suppose you have a tub filled with water and it rests on a scale so you can measure the weight. If you place an object in the tub, will the reading on the scale change? Clearly if the object sinks ...
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0answers
23 views

Finding the effective force constant in an accelerating frame [on hold]

Consider problem #16 here: http://www.aapt.org/physicsteam/2013/upload/exam1-2012-unlocked-solutions.pdf Let me share my thoughts, and hopefully someone can tell me where I am going wrong. ...
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0answers
21 views

2012 F=MA Contest #12 on tension [closed]

There is an interesting problem (#12) from the F=MA contest: My approach: Let the tension in the string supporting the hanging weight be $T$. Since the angles between all the strings are constant, ...
0
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1answer
85 views

Can we make a “Gravity Mill” based on principle(s) of Newton's cradle?

DISCLAIMER: Newbie/Wannabe Physicist. What's to stop us from making a "Gravity Mill" which is a bar/rod attached with weights on both ends and pivoted at the ...
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1answer
53 views

The velocity of the flowing coming out of the balloons?

Last day , when i was working on two interconnected balloons , a question was kicking my brains !!! This is the explanation of the question: First , suppose a system that composed of two spherical ...
1
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1answer
49 views

Acceleration of ball rolling down incline

Suppose you have some object (which can roll like a ball,cylinder,wheel,etc) rolling down an incline without slipping (moment of intertia $I=kmr^2$. I want to find the accleration of the ball as it ...
6
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3answers
745 views

Why don't we consider jerk in physics classes? [duplicate]

When i got more into physics, i started asking myself if just like acceleration represents the growth of speed, something else could also represent the growth of acceleration itself. And it came that ...
1
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1answer
22 views

Acceleration in a system equal for every body — why?

A 1 kg cart can slide frictionlessly on the table. The black weights each weigh 1 kg. The pulleys are frictionless. The task is to determine the acceleration of the cart. For the left-most ...
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0answers
55 views

Why golf balls travel faster if they spin?

From the book I have been given to read I found that balls spin due to the centripetal force but i am confused about how exactly do the resultant force causes it to spin and move forward about the ...
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0answers
41 views

Force Required to Move an Object at the Speed of Light [closed]

I am currently struggling on a problem that asks What magnitude of force is required to accelerate a $2~\text{kg}$ car to $1.00~\text{m/s^2}$ given its initial velocity is $90\%$ the speed of ...
0
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0answers
27 views

how can I use the Pythagoras theorem in the case of a block with mass on incline? [closed]

How can I calculate the acceleration of an object on an incline by using Pythagorean's Theorem? I'm confused between using Pythagoras' theorem or vectorial calculus to find acceleration. For ...
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0answers
15 views

Is the moment-curvature relation for an elastic beam general?

The relationship between the moment and the curvature for an elastic beam is $$M = -EI\kappa$$ Previously, I have only used this with small deflections in static calculations. I am currently working ...