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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Calculation of velocity via kinetic energy and momentum yielding different answer

I am attacking the given problem (as a preface I'm not asking to be spoon fed any answers, just looking for clarity from people much smarter than myself) A 15.0kg block is attached to a very light ...
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1answer
23 views

Comparing Brachistochrone curve with a Hypocycloid curve

I want to compare the time that it takes to slide a particle in a frictionless hypocycloid curve, so time would be given by the arclength divided by the velocity So I need first compute the ...
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2answers
34 views

Conceptual doubt about mechanic energy and two body problem [closed]

Suppose that two bodies are in plane, let's call the first m and the second M: In the first case m is moving in plane, so it has kinetic energy. M is attached at the origin (i.e not moving), so it ...
2
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1answer
27 views

Reaction to gyroscopic force

Just like the reaction of the weight of a body is a force acting on earth towards the body, where and in what direction does the reaction of a gyroscopic force act?
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1answer
90 views

Solve hanging rope question by using Lagrangian density [closed]

for this one, I can only do the first(a) $$V_{total}=\frac{mg}{l} \int_{x_0}^{d-x_0}{y(x)\sqrt{1+(\frac{dy(x)}{dx})^2}}dx$$ and have no idea about others.
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21 views

A Tricky Rotational Equlibrium Question [closed]

READ THROUGH QUESTION 64.(page-373) I HAVE SOLVED THE FIRST PART AND THIRD PART. ...
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2answers
38 views

Force needed to hold a book between your hands - not sure about the influence of friction

I'm looking at this problem: A student presses a book between his hands, as the drawing indicates. The forces that he exerts on the front and back covers of the book are perpendicular to the ...
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1answer
43 views

Particle disintegration (Landau & Lifshitz)

In the particle disintegration problem in the book by Landau and Lifshit(z), it is considered a particle with velocity $\vec{V}$ in the lab frame, which disintegrates into two particles with masses ...
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1answer
79 views

“Simple” physics problem without the solution [closed]

it's my first question here, i'm a french student in "classe préparatoire scientifique" and I find a problem on the net witch is : A slingshot consists of a rubber band that extends 3cm when you ...
2
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2answers
48 views

Free body diagram of this system and equation

I'm studying physics but in this question I can't figure out the free body diagram. link: http://prntscr.com/6j0t2u For $m_3$: $$T-m_3 g = m_3a $$ For $m_2$ along the y-axis: $$N - (m_2 + ...
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1answer
31 views

Kinetic and rotational kinetic energy

When a body is rotating on its own axis, and at the same time it is moving, does it possess both KE and RKE? So consider the case of the moon. The moon rotates on its own axis, and at the same time ...
2
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1answer
49 views

What is the initial acceleration? [closed]

What is the initial acceleration of mass 5M .The pulleys are ideal and the string inextensible. My attempt- 2Mg-T=2Ma (for 2M) T=Ma (for M) Solving we get T=2Mg/3 T-N=5MA (for ...
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0answers
44 views

During perfectly elastic collision of two objects $A$ and $B$, how much is the initial speed of object $A$ affecting the force applied to $A$ itself?

I got stuck in what seemed to be an easy problem. If two bodies $A$ and $B$ collide perfectly elastically and head-on what is the equation that gives us the forces applied to $A$ and $B$, given a ...
-1
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0answers
33 views

The force exerted by an object on another object [closed]

can someone explain how to do this physics question/conecpt? I'm really struggling with this concept and I don't know why xD WHAT FORCE DOES OBJECT A EXERT ON OBJECT B? Thanks so much!!
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3answers
59 views

Maximum acceleration for a vehicle [closed]

I'm in engineering school and we have a project: we have to build a amphibioues vehicle; I'm looking for a formula. Our vehicle has to go as far as possible with its unique source of energy, a ...
1
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2answers
123 views

Collision of two satellites

In a theoretical situation in which two identical satellites travelling around the Earth in opposite directions collided head on so that there velocities relative to the earth both became 0, would ...
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1answer
29 views

Derive Equation For a Cantilever in SHM

I am currently investigating how a hacksaw blade's time period of oscillation changes when I add mass to the end of it or when I change the length it is clamped at. I found the following equation ...
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2answers
60 views

Why is momentum conserved in inelastic collisions? How is it related to momentum-impulse theory?

First of all I want to mention, that I've found many questions around this site and in other websites dealing with my question; however, I don't think they answer my question fully. So I am here to ...
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0answers
24 views

imbalance calculation something with f m r in calculation [closed]

A road wheel has a mass of 10kg. It is found that its centre of mass (or gravity) is offset from its centre of rotation by 2mm. Calculate the out-of-balance force acting on the wheel when the vehicle ...
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3answers
100 views

Coriolis force on bullet vs airplane

Why do airplanes experience negligible Coriolis force while bullets experience the Coriolis force in long range shooting, even though the mass of airplane is much bigger than a bullet?
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1answer
50 views

Does precession of a rigid body change instantaneously?

I read some explanations of precession; this side for example summarizes briefly almost all what I have understood so far. But one thing bothers me: Following all this formulas, the precession ...
74
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6answers
8k views

Could we send a man safely to the Moon in a rocket without knowledge of general relativity?

I'm wondering if it's possible to send a man to the Moon using equations consistent with Newtonian gravity and without the elaborate tools of Einstein gravity. Are the predictions made by Newtonian ...
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2answers
54 views

How this formula for work follows from the definition?

If a particle moves along a path $\gamma : I\subset \mathbb{R}\to \mathbb{R}^3$ then the work done by a force $\mathbf{F}$ is defined by $$W = \int_{\gamma} \mathbf{F} = ...
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0answers
28 views

Derivation of natural frequency of free vibration equation [duplicate]

How can the equation for the natural frequency of free vibration of a mass-pulley system be derived from $F=ma$? Is this possible?
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1answer
29 views

Does the line integral definition of Work involve distance or displacement?

My textbook reports the following definition of Work: where ds is the infinitesimal displacement. I know that an infinitesimal displacement is usually denoted by dr and I also know that the ...
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2answers
16 views

Elastic behaviour of objects

If I strike my car with a wrench with enough force to make a dent in it, then it's obvious that I won't be able to produce any acceleration in the car. But I am applying an external deforming force. ...
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4answers
181 views

What was the amount of energy released in the 9/11 terrorist attacks?

I read somewhere on the internet that the amount of energy released by the terrorist attacks on the twin towers on 9/11 should have been of the order of 100 tons of TNT. This number surprised me, ...
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1answer
40 views

Is there a difference between normal forces and centripetal forces?

Is there a difference between normal forces and centripetal forces? Or they just mean the same thing? My textbook talks about centripetal forces, but not about normal ones.
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0answers
45 views

Classical Mechanics Help [duplicate]

I'm an undergraduate student majoring in physics. I don't know why but classical mechanics is giving me a lot of problems and I can't seem to grasp the concepts at all. So far we've been doing ...
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2answers
44 views

Why doesn't $x$ reach a constant for a block experiencing $v^n$ resistive force? [closed]

I am stuck on the Exercise 3.5 of Newtonian Dynamics by R. Fitzpatrick: A block of mass $m$ slides along a horizontal surface which is lubricated with heavy oil such that the block suffers a ...
5
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3answers
59 views

Finding the angular velocity of a rod hit at a distance from its pivot [closed]

A 1m long, 2kg stick is nailed to the wall with a single nail, allowing it to pivot and freely rotate at the end. A 1kg ball, with speed 3m/s makes contact with the stick at some distance x (unknown) ...
0
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2answers
68 views

If an object rests on a table, not accelerating, how much work do both the object and the table do?

Obviously, the net work done is zero, because there's no motion, but is the proper way to look at it that both the object's gravity and the table's normal force do zero work, or that one does positive ...
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0answers
40 views

How to make sure projectile does not go through a wall?

I'm struggling with a problem, in which I want to determine initial condition (initial velocity, and angle) given that I know my ball has to reach (final velocity, location), but I want to make sure ...
1
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3answers
92 views

Does circular motion cause centripetal force OR does centripetal force cause circular motion?

Does circular motion cause centripetal force, or does centripetal force cause circular motion, or are they both occurring hand in hand together instantaneously? One more question: If I project a body ...
5
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2answers
134 views

Breaking the Laws of Physics? (Walter Lewin rotation experiment)

Lately i have been watching the MIT Physics Lectures from Dr. Walter Lewin. I find his passion while teaching very fascinating and inspiring. Any way, in the end of the lecture about Torque he showed ...
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1answer
25 views

Spring pulled with one end fixed [closed]

As the title says, if one end of a spring of mass $m$ is fixed to say, a wall, and the other one is pulled at a constant velocity $v$ by some external agent, we have to find the kinetic energy of the ...
2
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1answer
24 views

Wave hitting a boundary with a mass on it?

If we have a transverse wave that is infinite in the $-x$ direction and terminate by a mass $m$, that is allowed to move in the $y$ direction at $x=0$ as shown in the diagram below: I think we can ...
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2answers
60 views

Question about circular motion of car turning

When we move round a roundabout there is a frictional force between the tires and the road that acts towards the centre of the roundabout in order to produce the circular motion. Why then do we ...
1
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1answer
64 views

If I bend a rod, will its moment of inertia change?

In the first picture, there is a homogeneous metal rod of length $2L$ and mass $M$. If it rotates around a normal axis passing by $O$ (which is the center of gravity), then its moment of inertia is: ...
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2answers
40 views

How to determinate the minimum period of oscillation for a physical pendulum? [closed]

A physical pendulum consists of a thin homogeneous rod of length $l$, suspended by a point $O$ at a distance $x$ from the center of gravity ($x<\frac{l}{2}$), oscillating in a vertical plane. ...
0
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2answers
49 views

Can $F=ma$ be used to calculate ground reaction force of someone walking/running?

Can Newton's second law of motion $F=ma$ be used to calculate ground reaction force of someone walking/running?
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3answers
61 views

Why does weight affect acceleration with gravity

I'm sure this question has been asked before, but my question is different, because it can't be answered with some formulae. My question is, why do heavier objects decelerate faster when moving away ...
1
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1answer
68 views

Falling rope problem (disagreement with solution found at Problem Set)

On a frictionless table there is a homogeneous rope of length $L$ and mass. We push the rope such that it immediately starts falling due to gravity. Find the velocity when the rope has fallen of ...
3
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5answers
220 views

How is Angular Momentum Conserved when Mass is Released?

I am not a physicist (math/comp-sci) but I understand that Angular Momentum is supposed to be conserved. I find this confusing because there seems to be many simple, common cases where a restrained, ...
0
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3answers
48 views

Will water in an oil-filled jar sink or float?

If I pour a spoon of oil on a jar full of water no doubt it will float. But if I were to pour a spoon of water on a jar full of oil would it sink? Why or why not?
2
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0answers
49 views

Motion of a charged particle in a “solid” charged sphere (accounting for radiation)

Consider a particle (point charge) with charge $q$ and mass $m$ that crosses into a uniformly charged sphere (with charge $Q$ and radius $R$). The trajectory of the particle is a diameter of the ...
0
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1answer
32 views

How to find the centre of mass of 3 masses (astronauts and a rock) connected by a rope

To be more specific on the problem, a 50kg astronaut, an 80kg astronaut and a 20kg rock are tied together by a light rope during a space walk. I am asked to find the center of mass. Now, I've chosen ...
0
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3answers
83 views

Forces on a ball thrown upwards

When a ball is thrown up in upward direction, it is said that force is in downward direction. Why we don't we consider the force given to the ball to throw up in the upward direction? Is there is no ...
4
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2answers
130 views

Can net torque $\sum_i\mathbf r_i\times\mathbf F_i$ be expessed as $\mathbf r\times$ (net force) for some $\mathbf r$?

Let $\mathbf F_i$ be forces each of which is applied on $\mathbf r_i$ of a rigid body. Then is there a position vector $\mathbf r$ that satisfies $$\displaystyle\sum_i\mathbf r_i\times\mathbf ...
0
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1answer
33 views

What is quantum states of a gas? Is it the principle quantum no.?

When we write that the possible quantum states of a system are $S=1,2,3.\dots$, how is that related with the four quantum numbers, especially with the spin of a particle? Also according to BE ...