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 path will an object in a cockpit take?

Situation: A fly is in the cockpit of a fighter jet, and flying directly in front of the pilot. The pilot becomes annoyed and decides to get rid of the fly by executing a sudden, high speed turn. ...
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1answer
61 views

How do I calculate stopping power?

Malcolm Gladwell made a claim in a recent talk that a sling with a stone going at 30m/s has the same stopping power as a .45 calibre handgun. How would I verify whether or not this claim is true - ...
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1answer
66 views

How does Newton's law apply to a person throwing snow onto their snowbank at the side of their driveway?

We know Newton's three laws: A object at rest will remain at rest, and an object in motion will remain in motion unless a external force acts upon it. If an unbalanced force acts on a object, the ...
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3answers
207 views

Tension on a string between two objects on a friction less surface [closed]

I just need my work checked here. Please let me know if I am correct. I had this problem in one of my test in which I did not get full credits. I am re-doing this(hopefully correctly this time) just ...
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0answers
26 views

Aerosol size distribution

When the size distribution of particles in an aerosol is obtained, there is always a bimodal distribution. The small peak accounts for the particles that are in sub-nanometer size range and the larger ...
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0answers
120 views

Equation of motion for a falling rod (with one end touching a frictionless surface)

I have a quick question about the equation of motion for a falling rod (with one end touching a frictionless surface). The end touching the surface is not fixed. I am given the moment of inertia about ...
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7answers
488 views

Metallic and glass sphere of same size released at a height

This question was in my exam today : A metallic and glass sphere of same size were dropped at same height. Which sphere would hit the ground first and why? I have thought about several things and ...
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1answer
130 views

When to use Cosine or Sine? [closed]

Three blocks of masses $M_A=15.0 \; \text{kg}$, $M_B=12.0 \; \text{kg}$, and $M_C=8.0 \; \text{kg}$ sit next to each other on a frictionless surface. A force $F=54.0 \; \text{N}$ acts on Block $A$ ...
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1answer
66 views

Why is it easier to turn a heavy hanging object?

Assume if we had a 2 tonne weight placed on ground attached with a rope that we can use to turn the object around. It will immensely hard to turn that object around by pulling the rope. However, if ...
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2answers
38 views

Solving actual weight lifted

I was wondering if anyone knew the formula to calculate how much force is required to lift a tire or any object by the edge. For example if a tire weighs 500 lbs (or has a mass of 226.8 kg). I would ...
2
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1answer
98 views

Lagrangian approach to spinning thread reel

I am trying to better understand Lagrangian dynamics and am struggling to complete the following question: A reel of thread of mass $m$ and radius $r$ is allowed to unwind under gravity, the upper ...
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2answers
51 views

Horizontal force on elevator?

I would like to ask the following: If an observer travels up or down in an elevator on earth, does he experience a horizontal force due to earth's rotation?
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1answer
35 views

Determining the horizontal position of an object [closed]

In my calc-physics class we were given the following question: A movie stuntwoman drops from a helicopter that is $30.0 m$ above the ground and moving with a constant velocity whose components are ...
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3answers
71 views

Information about newton's third law

Well I am still small student of physics, but as far as I know, Newton's Third Law states that, "For every action there is equal and opposite reaction." Now let me tell you how I understood ...
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1answer
38 views

Total energy of a body following circular motion

I learned that when a body rotates, its total energy is, $$energy=\left(\frac12\right)mv^2 + \left(\frac12\right)I\omega^2 $$ However, if an astronomical object is orbiting around the earth, is ...
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1answer
79 views

Confusion over the gravitational potential energy inside a sphere

I'm confused over the concept of gravitational potential energy inside a sphere. I understand that the gravitational potential energy inside the sphere is supposed to be a constant $U = ...
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1answer
54 views

How to obtain the distance traversed by a free falling body equation?

I know that the distance that a free falling body has traverse through time is given by $d=0.5*g*t^2$. I would like to know how to get to this equation to study a bit more how it was obtained. I have ...
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2answers
67 views

Equal and opposite reaction - forces coming in pairs - or just common sense?

I've never understood why the conservation of momentum law is taught in schools as "every force has an equal opposite reaction". To me a gun's recoil is self explanatory; the explosion sits ...
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1answer
82 views

Where do these formulas for an object being pushed up an incline come from? [closed]

An object on an incline with an angle $\theta$ is being pushed at constant speed. Constant speed implies $a = 0$. Because $F=ma$ and the object must have mass greater than 0. If I want to find the ...
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1answer
63 views

Vertical Circular Motion

I know that I can use conservation of energy to find the velocity of a particle at a point when it's travelling in a vertical circle by saying $$mgr(1-\cos{\theta})=\frac{1}{2}mv^2$$ then ...
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2answers
62 views

Determining if a particle is bounded or unbounded with motion in polar coordinates

Firstly, I determined the equation for the particles path for $k <-mV^2a^2$ as $u = {Ae^{\sqrt{\alpha}\theta}+Be^{-\sqrt{\alpha}\theta}}$ where $ \alpha = 1 + \dfrac{k}{mV^2a^2},$ $u = 1/r$ I ...
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1answer
66 views

Bernoulli's principle on a curve ball

I've seen a few excellent answers here on the Magnus force, which explains why balls with a spin will curve. However, my intuition is still telling me that the Bernoulli's principle would push it the ...
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6answers
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Pouring water in an aircraft while upside down?

What is the physics behind the following photo? Someone had told me that this is because the aircraft might be moving towards a lower altitude, but I am still not sure.
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1answer
43 views

Force on a line

Say you have a rigid line of mass $m$ and length $\ell$ along the $x$ axis and you apply a constant force $f$ at one end in a direction that is always perpendicular to the line, starting in the $y$ ...
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3answers
37 views

Why doesn't any object that doesn't have direct contact in a fast moving vehicle feel G-force or slam behind or ahead when braked or accelerated?

Why doesn't any object that doesn't have direct contact in a fast moving vehicle feel G-force or slam behind or ahead when braked or accelerated? For example when we are in a car (even with all ...
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2answers
59 views

Sign of Potential Energy

The mass is released at height $h$ above the spring, how far will the spring move? $E_i=mgh, E_f= kx^2/2+mgx$...why the second equation isn't $ E_f= kx^2/2-mgx$? Since it is below the "zero".
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2answers
47 views

How can I calculate the initial velocities of a set of objects with a consistent force?

I'm trying to figure out which object would have the largest time of flight when launched from a slingshot. To do this, I need the initial velocity. How can I calculate this if I know the mass and ...
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1answer
52 views

How to find the tension [closed]

A massless rod of length L attached to mass m and with axle to cart of mass M. The cart has a shape of equilateral triangle (edge L). the cart is at rest and its center of mass is above x=0 and a rod ...
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2answers
56 views

Force applied to two blocks [closed]

Due to application of force tow blocks of mass 1Kg and 0.5Kg move together. Each block exerts a force of 6N on each other. What is the acceleration by which both the blocks move?
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3answers
59 views

Confused about Impulse

Encountered a problem that involves impulse while studying for my exam and I'm not sure how to even approach it. I know that momentum is conserved, but I'm not sure how to relate that to avg force. ...
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2answers
48 views

Angle rotated by a rod when it's hit by a pendulum

Consider a pendulum of length $h$ with a bob of mass $m$ it is held horizontally at and angle of $90^{\circ}$ with the vertical. A rod of mass $M$ and length $h$ is pivoted at its upper end and this ...
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2answers
46 views

Homework Question involving Momentum [closed]

I'm trying to solve a homework problem as review for an exam I have tomorrow and I was wondering if someone could help explain it to me. It is as follows: You are at Lowe’s shopping for bricks ...
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1answer
75 views

How to model a rising helium balloon?

I'm trying to model the ascent of a helium filled weather balloon from 0km to 25km altitude. The plan is to eventually use a python script to calculate the time taken to reach 25km. However, I don't ...
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2answers
52 views

Rigid body rolling quesion

Hey, im having a bit of trouble with the problem in the added photo. So, there is the cylinder which is attached by a massless rope to a massless pulley, to a box (assume it is a pointed object). ...
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1answer
71 views

Ascertain the height an object has fallen from given force exerted and mass [closed]

An object of a given mass falls from an unknown height. If the force exerted by the object on contact with the ground is known, how would you ascertain the height from which the object fell?
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2answers
46 views

Distribution of Kinetic energy after an Impact

How does the huge amount of kinetic energy of some fast object like a meteor or rocket etc. gets distributed into various kinds of energy like kinetic, sound, light etc after making an impact with ...
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2answers
47 views

Taking pivot about an accelerating point

Given this question: A small ball of mass $m$ and radius $r$ rolls without slipping on the inside surface of a fixed hemispherical bowl of radius $R>r$. What is the frequency of small ...
4
votes
1answer
104 views

Variational calculus problem

I've been wondering lately about a problem that comes from, among other places, an old video game "Lunar Lander". In the game there is a spaceship that has a small tank of fuel, and you're supposed to ...
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0answers
19 views

Calculating Dynamics of a Thick Sheet of Material

So I'm working on a computational neuroscience problem, and I'm attempting to model skin dynamics for use in some perception models. The problem is as follows: Imagine you had a two dimensional sheet ...
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0answers
66 views

Partition Function of a three state particle system

I've just finished studying the partition function of a two-state particle system, where particles can have a 0 energy value or E energy value . That is: Where $t_j$ is a variable of value ...
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3answers
989 views

What is the cause of centripetal/centrifugal force?

What is the cause of centripetal/centrifugal force? When an object of mass $m$ is moved in a circular orbit, it experiences a centrifugal force radially away from the center. What is the cause of this ...
2
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0answers
67 views

Understanding gyroscopes

Considering the typical situation of a rotating bicycle wheel held by one end of its axle by a rope tied to the ceiling: gravity torque is the time derivative of the angular momentum, and in this case ...
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0answers
43 views

How to calculate how many can a stick hold?

I got two boxes, and one stick, two boxes are high enough for a human body. I put one stick between two boxes, like this: The boxes are yellow, and the stick is brown. So, I would like to put ...
4
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1answer
82 views

Speed to run a loop

So this guy was the first to run a loop and in this (german) article (and also in the video) a certain speed (13.8km/h) is mentioned. Why must he run at this speed and not just "as fast as possible"? ...
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2answers
45 views

is centrifugal release equal to explosive release

Scenario # 1 I put gunpowder and then a ball bearing in an old musket and fire the bullet. Scenario # 2 Lets imagine I had a motor with a disk on it and there was the same ball bearing stuck on the ...
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2answers
541 views

Is Einstein's Special Relativity completely inclusive of Newton's 3 laws of motion?

Relativity has always been explained to me (in books I've read, etc) as a superset of newton's laws - that is; it encapsulates all of Newton's mechanics in addition to other effects (observer effect, ...
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1answer
78 views

What happens to bodies that lift each other up? [closed]

Person A and Person B are same person (theortically). They both weigh 800N. They both can vertically lift 1000N. They want to ...
3
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1answer
131 views

Chain with mass gradient problem

This is the problem, basically. Now my question is about the approach. Mine, and my teacher's. I would like some help as to which one is correct... Mine: As the whole chain is in equilibrium, the ...
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2answers
50 views

Maximum range for projectile thrown from a mountain [closed]

I have doubts with the following problem: A projectile is fired from the top of a mountain that has a downward slope with angle $\phi$ from the horizontal. The initial velocity of the projectile is ...
2
votes
1answer
79 views

Maximum permissible speed while going down a ramp

So, I was playing hill climb racing and I noticed that if we move with high speeds towards a ramp going down we just jump it off. While lower speeds, help us to stay in contact with the ramp. ...