Classical Physics

...when a man with a mass of 90kg runs 100m at a velocity of 10m/s? what is the work done when the same man walks 100m at a velocity of 1m/s? (this isn't a homework question; i'm trying to grasp the concept)

In Greene's Elegant Universe, he describes gravity as a sort of pressure, or at least that's how I inferred it. That objects can be thought of as being "squeezed" into this vacuum of spacetime. So the larger the object, the more it warps spacetime having been pseudo-squeezed into the fabric. With that predictably oversimplified analogy, that got me wondering where the greatest point of pressure can be found. For instance, is the pressure greater on the surface of the earth, or at it's core? I'm assuming the pressure decreases as you travel away from the surface of the earth toward space, but I'm not sure how that pressure changes when traveling away from the su…

Hey there all, I'd like to try and make a program that simulates 2D celestial collision (star with planet, planet with planet, star with star, etc.). Now, I know that something like this is probably impossible to simulate precisely, and if I even wanted to get close I'd have to call in some serious computer-power favors at NSA, but I'm not looking for something I can sell NASA. I'm just looking for an approximation. Could anybody here tell me what I should read up upon, which topics I should become familiar with, what kind of math/physics knowledge I will be needing, different approaches I can try, etc.? Again, I'm not looking for a precise way to simulate a celestial…

How would that be possible, without a sophisticated computer program which computes a 2D object under a 3D abstract? Conecputually, it is very easy to imagine. But computationally, it should be near-impossible.

Hi! Can anyone explain the involvement of centripetal force in the operation of a washing machine? And how the spin dryer of the machine is able to dry the clothes?

If the Doggfather were to literally push Stephen Hawking...why doesn't Snoop Doggy Dogg roll backwards?

I have a rod with a fixed base, a hinge. It starts to fall sideways (rotating). Using the conservation of energy, how is the angular speed related to the angle with the ground?

I have to perform an experiment by releasing an air filled baloon from height of 2 m and simply using wristwatch and ruler give some explanations when would it reach it's terminal velocity, if somebody could please help me or just give me some clues how to solve this problem? I would really appreciate and thanks in advance!

Hi to all! I'm developing a six degree of freedom which uses the oblate rotating Earth and which wil be used to simulate the motion and the trajectory of airplane and spacecrafts around the world (so no simplification is actuable). My work is based on Steven's "Aircraft Control and Simulation" and is pretty similar to this one: http://www.mathworks.com/access/helpdesk/help/toolbox/aeroblks/6dofecefquaternion.html One of the requirements is that it is possible to use the same model also for calculate the trim condition. To do that I need the variation of velocity vector expressed in body axis and the relative angular acceleration ([math]\dot{\vec{V_{b}}}[/math] and [m…

I'd liek to understand how conservation of energy applies when using a lever. For example, you didn't put that much work in when using a lever to hoist up something heavy. Layman's terms please

I have a Camera lens (a 300mm) that I use to photograph the moon and other far away things, the "problem" I have is that when I set the lens to Infinity for the Moon for instance it`s a little bit out of focus and I have to turn it back just a little bit to be in perfect focus. so my question is, when it`s set to infinity (just beyond what is perfect focus for the moon), what IS it focusing on? what sort of distances am I looking at for that setting be perfect?

can someone explain how an automatic aerial on a radio works??......... motor could it be what mechanisms makes it pop out All help apreciated

Stanford has a pretty good series of lectures on Classical Mechanics. Any one else care to share some good online lectures?

hi guys!! I recently learned about Newton's laws and at a moment, the teacher told us that the Newton's first law(a body continues to maintain its state of rest or uniform motion unless acted upon by an external unbalanced force)is always true unless the studied system has a speed near, = or > to light speed; So now I wonder if light speed was 10m/s, how would the world look like and how would Newton's laws be changed?

Why is the velocity of a fluid high where the pressure it exerts is low, and why is the velocity of a fluid low when the pressure it exerts is high? Please explain. Thank you.

Hi... I was thinking how fascinating “buoyancy” is; and I came to the conclusion that instead of thinking of something floating to the surface “in water” it’s better to think of it being squeezed to the surface. (and was wondering if I would be wrong?) Now I’ll walk you through my thinking behind this (and of course keeping in mind - that I’m just guessing, based on what I know). So let’s get the ball rolling: First of all - I know - “they don’t know” exactly what gravity is They say that it’s a warping of space and time (meaning, it’s not electric, chemical, magnetic and or “whatever”)... It’s this - what they call - a warping of space and time ... Now …

I am settling into a new home and a candle is lit on the table. It looks orange and bright. It is nearly dark outside, and I see two reflections in the double-pane windows. The first is true to color; the second is a bit smaller, but pale green in color. Why is this tweaky image happening?

1. Jason takes of across level water on his jet-powered skis. The combined mass of Jason and skis is 75 kg. The skis have a thrust of 200 N and a coeffcient of kinetic friction on water of 0.1. Unfortunately, the skis run out of fuel after 57 s. What is Jason's top speed? I am just doing sample problems for my test today please help thank you

How do Aeroplanes actually stay in the sky? does anyone know ?Exactly how?

A fisherman casts his bait into the river at an angle of 25 degrees. As the line unravels, he notices that the bait and hook reach a maximum height of 1.7 m. What was the initial velocity he launched the bait with?

I admit, this was on a television show. But it IS very perplexing. Isaac Newton was the scientist who discovered gravity. Well, the TV show said he also went into atoms, but he was almost TOO long ago to know about that. Anyway, supposedly he thought that electrons circled the nucleus of an atom because of gravity. A few minutes after I watched that, I noticed something: If the electrons orbited the electron because of gravity, then they would also have to eventually collide with the nucleus, and the atom would likely no longer exist. Every object would be imploding really fast- and I really think that I would be consisting of two or three atoms right now if that was …

im trying to construct a hoverboard can ne1 help me

Is it possible to include a picture to assist in the question that one is asking about in this space? I have question that can really only be asked with reference to an illustration that why I ask. Thanks.

As I was watching CO2 bubbles accelerating upwards in my glass of coke and wondered how fast they'll eventually go in a very tall glass, in other words what would be a bubble's terminal velocity, I realized that although it would be interesting to calculate an estimate I needed hydrodynamics, which is something I hate. I've been brushing up my rather non-existant previous hydrodynamics knowledge but I'm still a bit confused. Are small bubbles (let's say 0.001m in diameter) practically rigid spheres? That would certainly make things easier, as I could just use the "normal" terminal velocity formula, right?

Here’s part of a problem from Tipler Physics for Scientists & Engineers:- In a Sci-fi short story written in the 70s, Ben Bova described a conflict between two hypothetical colonies on the Moon- one founded by the USA the other by the USSR. In the story, colonists are from each side started firing bullets at each other, only to find to their horror that their rifles had a high enough muzzle velocity that the bullets went into orbit. (a) If the magnitude of free-fall acceleration on the Moon is 1.67m/s^2 , what is the maximum range of a rifle bullet with a muzzle velocity of 900m/s? (assume the curvature at the surface of the Moon is negligible). I read …