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 confusion regarding friction

Suppose there is a block which is being pulled by two forces A,B in opposite direction(as shown in figure). If we have no information regarding the forces $A$ and $B$, can we tell whether there is any ...
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3answers
151 views

How does The work done in going around any path in a gravitational field is zero implies conservation of energy?

In The Feynman Lectures, Feynman states: The work done in going around any path in a gravitational field is zero. This is a very remarkable result. It tells us something we did not previously ...
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1answer
47 views

Applying impulse to velocity

I'm writing physics engine and so far got some good results but stuck on 1 task i would like to ask. Got some mistake in my formula. Here is a question:Imagine 1 square colliding into another one. ...
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0answers
123 views

Magnetic field on axis of solenoid

So first I'd like to say that I have asked similar questions to this one. However, all the answers involve a level of calculus that I do not yet know. (Still on limits, going to spend the rest of ...
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2answers
123 views

How to understand an equation physically?

I've been reading some Feynman's books. There's a point that intrigues me. It's the fact how we understand a physics equation, not only mathematically, but digging deeply into its roots as a ...
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14answers
8k views

Is it possible to walk in a friction-less world?

Is it possible to walk in a frictionless world. I think you won't be able to walk because walking depends on friction acting on your feet. I think about it like an ice rink because when you try to ...
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1answer
50 views

What does the second solution in an elastic collision represent?

A ball of mass 2 collides with a stationary ball of mass 1 elastically! In finding the velocities i end up with two solutions and am not sure how to understand the second solution Simplified ...
2
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2answers
389 views

Why does locking the rear tires on a vehicle cause it to spin?

Handbrake Turns are often used in motor-sports and stunt driving to turn around tight corners. Essentially, the driver applies the handbrake as he enters the turn, in order to "kick out" the back end ...
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1answer
77 views

How does a skater moves by pushing sideways?

Take a look at this video http://www.youtube.com/watch?v=EmMf91AVUXc or take a look at the following screenshot. As you can see, the skater pushes almost perpendicular to the direction of movement ...
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1answer
26 views

Why the absolute temperature used in radiation equation of Stefan Boltzmann law ? [closed]

Why the absolute temperature used in radiation equation of Stefan Boltzmann law ?
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3answers
814 views

Tension in a rope

In an ideal case, we assume strings and ropes to be massless and having same tension throughout. However, I was doing some questions which involved a rope with mass. The question was that if a ...
2
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2answers
108 views

Will the water go inside the moving water bottle?

Let's say that there is a empty bottle in the water moving at a high speed like this: My question is: Will the water go inside the the empty bottle when the bottle is moving at a high speed? If ...
4
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4answers
682 views

A confusion regarding an example in The Feynman Lectures

In The Feynman Lectures, In the chapter entitled Work and potential energy, Feynman states: The work done in going around any path in a gravitational field is zero. This is a very remarkable ...
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1answer
56 views

Condition for 2 bodies to move together

The condition for 2 (or more) bodies to move such that they are always in contact, is that their accelerations (and velocities) along their common normal should be same. Can someone explain why this ...
2
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1answer
142 views

General second order system and mass spring damper in control theory

I am studying control theory and most textbooks and web resources define a general second order system in the $s$ domain as $$ G(s) = \frac{\omega_n^2}{s^2+2\,\zeta\,\omega_n\,s+\omega_n^2} \, .$$ ...
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0answers
88 views

Time-dependence of mass of rolling sphere

I'm working on a problem for fun trying to find an expression for the mass of a sphere as it rolls off the side of an already rolling sphere (I'm assuming the top sphere is a 'snowball', meaning it ...
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1answer
89 views

Rocket equation derivation, question about signs

My question is about signs in the derivation of the rocket equation. Considering a rocket of mass $m$, its momentum at time $t$ is $p(t)=mv$. At time $t+dt$ it ejects a quantity $dm$ so its momentum ...
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3answers
62 views

Problem with black holes?

I understand that black holes are formed when supermassive stars (>10 times the size of our Sun) die. When they die, their cores continue to shrink. I have read that eventually the core reaches a ...
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3answers
139 views

Forces and the light

Do external forces can affect the light? Can any external force make the light accelerate? And if it can, will it accumulate mass? (according to the second Newton's law of motion $m = F/a$ ) We know ...
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2answers
165 views

Newton's laws and the maximum speed

According to Newton's second law of motion : $F = ma$ In an certain occasion, we exert 2 forces (the magnitudes of the forces are the same) on 2 different objects, Object A and Object B, in the same ...
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2answers
922 views

Does body weight affect the speed when going downhill on a mountain bike?

We know heavier objects fall faster when dropped at certain height. I was wondering if I am going downhill on my mountain bike without any peddling, will I travel faster or slower because I am fat?
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1answer
38 views

Isn't the data insufficient in this problem?

take a look at this problem: a 1000 kg roller coaster car is towed at a constant speed up a 40 meters hill, what is the work done by the tow rope? don't we need the slope of the hill and the static ...
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1answer
160 views

How exactly do walking canes and crutches help?

I am reading introductory physics, and there is a chapter on equilibrium. In the chapter, the author mentions how devices can exploit distribution of forces to help those that are physically ill, via ...
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3answers
4k views

A simple derivation of the Centripetal Acceleration Formula?

Could someone show me a simple and intuitive derivation of the Centripetal Acceleration Formula $a=v^2/r$, preferably one that does not involve calculus or advanced trigonometry?
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2answers
152 views

Why does linear momentum change in this problem?

I found this problem in a Irodov's book. It's asked to find the momentum increment of the bullet-rod system. I wonder why the system momentum changes. They argue this: The bullet-rod system is ...
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1answer
74 views

Why aren't the weights of the beads considered in this equation?

I was solving this problem: A ring of mass $M$ hangs from a thread and two beads of mass $m$ slide on it without friction.The beads are released simultaneously from the top of the ring and slides ...
4
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4answers
225 views

Calculating how fast a mass needs to travel in order to launch itself from a hill

Today I was driving on a hill side and on the opposite lane this very careless gentleman was traveling at a very high speed on a large truck that I surely thought his truck would of lifted off the ...
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1answer
84 views

Shooting a bullet in space [closed]

Imagine I was in space holding a gun and I shot a bullet from it. Do I go back? Or does the bullet move forward? Or both of us go in the same speed at different directions? Or what? Please Explain. ...
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7answers
916 views

What is inertia of a body?

The definition of inertia is "Inertia is the resistance offered by the body whenever its state of motion is changed." What is inertia of a body? Is inertia actually a force exerted by the body? If ...
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1answer
51 views

How to Calculating power using smart phone?

I'm writing a smart phone app and one of it's functions is to calculate power of the vehicle that the phone is travelling in. The user enters the total weight of the vehicle and the app uses the ...
3
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2answers
188 views

Using the product rule to expand Newton's Second Law?

Newton's second law says that $$F=\frac{\text{d}p}{\text{d}t},$$ where $F$ is the net force on a body. My question is, why can't the product rule be used to yield ...
2
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7answers
828 views

Free fall into circular motion

If I'm on a roller coaster free falling from height $h$ and then suddenly start going into horizontal motion with a radius $r$ of turn what is the $g$-force I experience? I worked out the equation ...
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0answers
47 views

What factors are influencing a woosh rocket?

Not sure if this is too much chemistry, but I'll try: If I fill a plastic bottle with a small amount of rubbing alcohol, shake it around and hold a match to the bottle neck, I'll get a flame wooshing ...
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3answers
2k views

Calculate acceleration from power [closed]

I am currently programming a simple computer space ship simulation. This is just for fun to train my programming, 3D graphics and a little bit of physics skills. What I want is the user to pick a ...
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2answers
256 views

Why does mechanical energy have to equal zero to find escape velocity?

A object orbiting the earth has total mechanical energy equal to \begin{align*} E^{mech} = \frac{1}{2} m v^2 - \frac{GMm}{r} \end{align*} with $M$ the mass of the earth and $r$ the distance. My course ...
2
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4answers
1k views

Does stopping the same bike and rider at the same velocity with the front brake require less energy than the back brake?

It's the same body made by the rider and the bike moving at the same speed. So, even though braking on the front/back alters the normal forces on the opposite wheels thus creating more friction with ...
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1answer
57 views

Centrifugal force on objects rotating around Earth

Suppose two objects travel around the equator on Earth at the same speed, $v$, in opposite directions, where the speed $v$ is measured relative to the Earth's surface. Will they experience different ...
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1answer
39 views

Effects of vertical circular motion to the body weight

Our body weight will experience the differences when moving at constant speed in a vertical circular motion such as roller coaster. Why do we feel heavier when at the bottom of the loop and lighter ...
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1answer
71 views

Changing linear to angular velocity

Suppose a 1m rod with a hook is travelling at $v$ m/s, and the hook is caught on a hanging line. The rod will change its translational motion into rotation around the hook. Since it is not an ...
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2answers
417 views

Why is the net work done in a pulley-string system zero?

In any pulley system, where the pulleys and strings are massless and frictionless, why is the net work done by Tension zero?
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1answer
123 views

Torque-direction of rotation

Taking moment about $A$, the mass of 2.0g and 0.50g is rotated in the clockwise direction is because they are both directed in downwards position? while $R2$ is acted in upward direction, so it is ...
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2answers
60 views

Can two artificial bodies be built in space and be made to orbit each other?

Would it be possible to make artificial constructs (satellites) orbit each other? I looked at the gravitational laws, and nothing seems to suggest that this is not possible.
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3answers
113 views

Can the anti-torque of a motor be used to spin a space vehicle about it's axis?

Imagine an electric motor together with its power supply in space. What exactly will happen to it if it is suddenly powered? Will it spin about its axis, or it will experience no motion relative to an ...
1
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1answer
40 views

Are coefficients of friction invariant by switching the materials?

I don't have the ability to make the experiment to answer these questions : Let $A$ and $B$ be two materials. Is the static coefficient of friction of $A$ on $B$ equal to the static coefficient of ...
10
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2answers
2k views

Can a mouse rotating a wheel violate conservation of angular momentum?

I have been thinking on the following problem. Part I. Imagine we have a mouse enclosed in a rigid box. We placed the box on a frictionless surface (ice might be a good example). Can the box start ...
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0answers
62 views

Is it true that whenever any non rigid body moves, there must be a delay between the ends? [duplicate]

Very sorry if this is still considered a duplicate to this, but unfortunately the answer to this question cannot address this because mine is a nonrigid body and involve biological locomotion concepts ...
0
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1answer
51 views

Period to calculate the universal gravitational constant

To calculate the torsion constant in Cavendish experiment we need the period of it, so my question is if I need to measure the time the rod with two small spheres takes to do an oscillation (with an ...
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0answers
92 views

Question about Elon Musk's Hyperloop Suspension [closed]

So one of the proposed suspension systems that will be used on the hyperloop include the externally pressurised air cushions. These cushions lift (or atleast help lift) the capsule and reduce drag ...
2
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1answer
38 views

Is motion along the $x$ and $y$ axises independent with quadratic drag?

It's often stated that motion in the $x$ and $y$ axises are independent, so that changing the $x$-velocity will not influence changes in the $y$-velocity. To me it seems that with quadratic drag (drag ...
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2answers
96 views

Exerting force upon oneself in space

In space, there is no friction or forces of resistance of any kind, so I would assume that if two people were in space and one of them punched or pushed the other, the person upon which the force was ...