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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Tension in a string with pulley and two objects at opposite ends

Tension is confusing me. According to my understanding of tension the tension in a string is uniform but while going through the solution of a problem I read that tge tension on the left part of the ...
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4answers
15k views

Would a light or a heavy ball roll fastest down a slope?

A small, light ball and a larger, heavier ball are released from the top of a slope. Which will move further? which will come down faster?
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Acceleration as a function of time in Newtonian gravity [duplicate]

In Newtonian gravity, you have acceleration as a function of separation distance $r$ as $a(r) = GM/r^2$. I need to derive acceleration as function of time, i.e. $a(t)$. PS I got into this when I ...
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1answer
191 views

Coriolis Effect vs airplane

So, if I build a highway from north pole towards equator and sit in a car, speed pretty fast towards it, I should feel force with the Earths rotation due to the different rotation speeds of this ...
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1answer
34 views

Cable wakeboard raley

Illustration of the problem: http://www.youtube.com/watch?v=OWRixptJaRo The non physics solution: http://www.youtube.com/watch?v=FRwHcJjfCR4 My first approach to learn this was to follow youtube ...
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0answers
49 views

Find the Kinematic degrees of freedom of the following contraption

In the above mechanism it is required to find the generalized coordinates to write equation of motion of the MDOF system. I just want to ask how do we actually approach such a problem? How to identify ...
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1answer
23 views

Newtonian mechanics, block on conveyor belt [on hold]

The coefficient of friction $\mu$ between the block and the conveyor belt is $0.3$ and the belt is moving with a speed of $6m/s$ when a block is dropped onto it from rest. Find the time when the ...
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1answer
17 views

The directions of the frictional force acting on the cylinder while ascending and descending cylinder

A cylinder rolls up an inclined plane,reaches some height,and then rolls down without slipping throughout these motions.The directions of the frictional force acting on the cylinder (A)While ...
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1answer
125 views

What's my $\mathrm dM$? Gravitational Potential inside a circle of mass

I'm trying to find the gravitational potential for an arbitrary point within a ring of uniform mass density. The point is constrained to be in the same plane as the ring. So we start with: $$\Phi=\...
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2answers
1k views

Average Force vs Net Force

The F in $$Impulse = F*t$$ is said to be the average force. For a ball dropped vertically onto a horizontal surface, the average force, F, on the ball from the floor is: $$F = \frac{\Delta{p}}{t}$$ $$\...
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2answers
38 views

Friction, Dynamics question

In the given question $F=2t$ where $t$ is time in seconds for which the force has been applied. Friction exists only between $A$ and $B$ with coefficient of friction $\mu=1/2$. Here we can easily see ...
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1answer
31 views

Why does galilean invariance imply that particles that start rest stay on the same line?

I'm reading Arnol'd for self study. I'm struggling with this question: "Show that any system of two particles will remain on the same line that connected them at the initial moment, if they started at ...
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12answers
2k views

Is the distance between the Sun and the Earth increasing?

M = mass of the Sun m = mass of the Earth r = distance between the Earth and the Sun The sun is converting mass into energy by nuclear fusion. $F = \frac{GMm}{r^2} = \frac{mv^2}{r} \rightarrow r =...
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1answer
620 views

Rolling a ball into a cone; what should the forces overall be?

This is my solution to finding angular displacement/velocity/acceleration on cone so far. Consider a cone, with an apex of half-angle $\psi$ pointing down, and a height of $h$. If I roll a ball into ...
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2answers
32 views

Springs acting on a car [on hold]

I am trying to solve a problem but I can't figure out why the answer comes out to be what it is: A man of 80kg enters a car and compresses the 4 springs of the car, causing a change of 1,2cm from ...
2
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1answer
2k views

Calculating the moment of inertia in bifilar pendulums

I'm an A2 student, and I've been looking into how experimental and theoretical determined mass moments of inertia differ. I came across a method (search Youtube for Measuring Mass Moment of Inertia - ...
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1answer
36 views

Projectile motion with air friction force/resistance [on hold]

We have to find the x (the distance, if you didn't know that then I'm not sure if you should be doing this problem) that the projectile travel during the time in the air until the time it hits the ...
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1answer
28 views

What is the tension on the horizontal rope in this conical pendulum setup? [on hold]

A rope is attached to the top of a straight pole. A person of 890N and a seat of 201 N are attached to the end of this rope. The person rotates 37.4 revolutions/min in the horizontal plane while the ...
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0answers
20 views

Loop the loop question: A marble of mass $m$ and radius $r$ rolls along the looped track in the image [on hold]

A marble of mass m and radius r rolls along the looped track in the image: What is the minimum value of H if the marble is to reach the highest point of the loop without leaving the track?
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3answers
57 views

What is acceleration of A and how to approach such accelerating pulley problem [on hold]

As shown in figure A and B are free to move pulley and rope are mass less, there is no friction at all between any two. Now my question is because of tension in rope, A will move left but how will B ...
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1answer
15 views

Wear rate with sliding speed

I read so many research studying the effects of sliding speed on wear using pin on ring testing machine all of papers said: when the sliding speed increase the wear rate will increase because the true ...
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5answers
8k views

Why do archery arrows tilt downwards in their descent?

In the movies, arrows shot into the air rotate so that during the descent, the arrow head hits ground first. What is the source of this angular momentum? It would seem that the bow string exerts a ...
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1answer
42 views

Why do Newton's laws hold in a normal and tangential coordinate system?

In my book it says: 'When applying the equations of motions, it is important that the acceleration of a particle be measured with respect to a reference frame that is either fixed or translates with ...
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3answers
688 views

Infinite grid of planets with Newtonian gravity

Assuming only Newtonian gravity, suppose that the universe consists of an infinite number of uniform planets, uniformly distributed in a two-dimensional grid infinite in both directions and not moving ...
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1answer
773 views

Is running in a zigzag helpful in avoiding being shot by an arrow? [on hold]

Two people A and B start at a certain point. B runs away from A to another point. A shoots arrows at B. Is it helpful for A to run in a zigzag rather than in a constant direction? To be more ...
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0answers
19 views

Derivation of differential governing equation of Hartnell governor? [on hold]

I tried to derive the differential governing equation using energy conservative method and newton's second law, but I came up with very large and complex equations, even with assumption of small angle ...
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1answer
35 views

Maximum range in projectile motion (elliptical path)

Elementary Newtonian mechanics tells us that if a projectile is shot at 45 degrees from the ground, and a downward gravitational field is acting on it, it will follow a parabolic path and achieve ...
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0answers
77 views

Constrained motion [on hold]

All speed shown are with respect to ground. Then we have to find the speed of block B with respect to ground. I tried it by two methods, but got different result why?
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0answers
21 views

Force needed question [on hold]

I am standing on a ladder 24 ft. in the air,The angle of the ladder is 65 degrees and I weigh 200 lbs and the ladder weighs 65 lbs ,How much force would be needed to lift the ladder off the ground,...
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2answers
109 views

Physics behind seemingly-impossible “rice bowl suction” Guinness world record? [duplicate]

By pressing a rice bowl on his abdominal muscles, Zhang Xingquan was able to create enough suction to pull a 36.15 tonnes heavy train for 40 meters Source: Guinness world records website. How does ...
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1answer
298 views

Question on Binet's equation

Is there a difference in Binet's equation when the force acting on a body is attractive and repulsive? I mean, if the force has a magnitude $F(r)$, is it Binet's equation always $$\frac{d^2u}{d\...
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1answer
93 views

Expressing virtual force in terms of muscle contraction force

Two bodies connected with a hinge joint with axis in J. They also connected with a muscle at points M and M`. I’m trying to express virtual force Fv in terms of muscle force Fm acting at the point M ...
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2answers
29 views

Work and energy example [duplicate]

The normal definition of Work, as far as I have read, is: Energy is transferred through work. But I just heard an educationist state this example, where there is a weightlifter who keeps up a huge ...
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1answer
87 views

Sliding blocks problem

My first post here, so I apologize if this is duplicated elsewhere. It IS a "homework" problem, but it's public domain, a posted exam with answers... http://www.mun.ca/physics/undergraduates/...
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1answer
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3
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2answers
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Force applies to sphere not on center of mass?

Is this true: When force is applied to a sphere NOT on center of mass (COM) then the sphere will move the same way as when force is ON center of mass, because the sphere is symmetric in every ...
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0answers
47 views

Non-diagonalisable system of ODE from structural mechanics

Consider a basic mechanical system driven by the second order ODEs $$ \mathbf{M\ddot{x}+D\dot{x}+Kx=0}$$ where the mass matrix $\mathbf M$ is positive definite; no specific assumptions other than ...
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2answers
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Verifying directions of forces during pure rolling?

Let us take a cylinder on a rough horizontal surface. The cylinder undergoes pure rolling A vertical downward force acts on the cylinder to produce a clockwise rotation. The point at which it acts ...
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1answer
31 views

Equilibrium of rigid body [on hold]

A uniform beam $AB$ of length $2l$ rests with end $A$ in contact with rough horizontal ground. A point $C$ on the beam rests against a smooth support. $AC$ is of length $\frac{3l}{2}$ with $C$ higher ...
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1answer
43 views

Projectile question doubt [on hold]

A hunter wants to shoot a monkey with an arrow by launching the arrow at a speed $v_0$ at a distance of $L$ from the base of a tree of height $H$ on which the monkey is sitting. Now on watching the ...
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1answer
156 views

Is the double pendulum an example of a strange attractor?

Imagine a pendulum to which is attached another one (not necessarily the same length). Does this pendulum, when you let it go (which can be done in many ways but let's keep the total potential ...
3
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0answers
39 views

How does the bowling computer know I'm right handed? [on hold]

I went bowling the other day and after I rolled my first ball I was suprised it was written on the screen that I was "right-handed". How was that figured out? My first guess is that there is ...
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2answers
103 views

Work energy theorem explanation

So there is this problem in my head, it may seem very simple, but I need an answer. The problem is, we have some object, and we apply a force by our hands with a constant speed from a position (1) to ...
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2answers
56 views

Why there is an extra componet of force in this Equilibrium state?

I have a question about the forces on a body at equilibrium. Look to this image: here i draw a man standing with a pen on earth. And I think that I draw all possible forces on it. They are as ...
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0answers
31 views

How to solve this stationary object collision problem? (Answers must be numerical.) [on hold]

If a mass (m) is traveling at a positive velocity and collides elastically with another mass (m*2) that is at rest, what are the ending velocities of both masses? So far, I've gotten that v1f = -1/3(...
2
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2answers
90 views

Can energy conservation be derived from Newton's Laws?

Can the idea of energy conservation be derived from Newtons's laws? From inspection of his laws you can vaguely discern a relationship but I want to know of you can manipulate his laws to prove it. ...
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3answers
357 views

Are Newton's laws followed in non-inertial frame of references having all their objects and observer moving with same acceleration?

Consider a hypothetical scenario. In our universe there are two merry-go-rounds 1 and 2 and a distant planet. There is no other object having mass. There is a robot X on the planet. There are two ...
2
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2answers
115 views

All reference frame are inertial? Where is the flaw in reasoning?

This is my first post here. I have a line of thoughts which might be wrong but I couldn't find the error. Suppose we have a point mass subjected to an arbitrary force $F$. In the lab reference frame ...