skykilo Posted January 9, 2004 Posted January 9, 2004 (edited) Nevermind, I'm going to adhere to my original policy of not discussing science here. You won't hear anything else out of this jackass! moving at the speed of stupidity Edited January 9, 2004 by skykilo Quote
Dru Posted January 9, 2004 Posted January 9, 2004 "I am beta testing the new Mars rover and you aren't " Quote
Stonehead Posted January 9, 2004 Posted January 9, 2004 Catbird...think about that for a second. Who says the planets travel at the same velocity? This is true. A planet's velocity depends upon several factors. 1. The sun's mass 2. The planet's mass 3. The distance between them. It rotates at a speed where there is a neutralization of angular momentum. The outward force is based upon the planets mass and the speed it is rotating at. The inward force is based upon the equation F=G*M*m/r^2, where G is the universal constant 6.67 X 10^-11 NM^2/kg^2, M is the mass of the sun in kg, m is the mass of the planet is kg, and r is the distance between them in meters. Incorrect. The mass of the sun has no effect on it's orbital velocity. Only the mass of the orbiting object and the radius of the orbit have an effect on orbital velocity. The inward acting force (centripetal):M plannet*(v^2/r) "Outward acting force"??? This is commonly called "centrifugal force", and doesn't exist. There is no outward acting force on an object travelling with uniform circular(or satellite) motion. Got notes, fixed mistakes!! You are right about the sun's mass, now that I think about it. Centripital Force is inward, but there most certainly is a force acting outward. Centrifugal Force, or the tendancy of the planet to escape it's orbit definately exists, and is the same as it's Centripital Force. That is why the planet stays in it's orbit. Uh, wouldn't that account for the 'slingshot' effect or not? escape velocity? Quote
Doctorb Posted January 9, 2004 Posted January 9, 2004 Catbird...think about that for a second. Who says the planets travel at the same velocity? This is true. A planet's velocity depends upon several factors. 1. The sun's mass 2. The planet's mass 3. The distance between them. It rotates at a speed where there is a neutralization of angular momentum. The outward force is based upon the planets mass and the speed it is rotating at. The inward force is based upon the equation F=G*M*m/r^2, where G is the universal constant 6.67 X 10^-11 NM^2/kg^2, M is the mass of the sun in kg, m is the mass of the planet is kg, and r is the distance between them in meters. Incorrect. The mass of the sun has no effect on it's orbital velocity. Only the mass of the orbiting object and the radius of the orbit have an effect on orbital velocity. The inward acting force (centripetal):M plannet*(v^2/r) "Outward acting force"??? This is commonly called "centrifugal force", and doesn't exist. There is no outward acting force on an object travelling with uniform circular(or satellite) motion. Got notes, fixed mistakes!! You are right about the sun's mass, now that I think about it. Centripital Force is inward, but there most certainly is a force acting outward. Centrifugal Force, or the tendancy of the planet to escape it's orbit definately exists, and is the same as it's Centripital Force. That is why the planet stays in it's orbit. Wrong. F=m*a. There is not outward acceleration, therefore there is no outward acting force. For example, take a mass on a string, with the mass moving with uniform circular motion about some center. The string exerts the centripetal force. Cut the string, and the mass will travel at a tangent to the circle. If there were an outward acting force, the mass would leave its orbit at some outward angle. This does not happen. The Centrifugal Force is a MISCONCEPTION. Quote
Dan_Harris Posted January 9, 2004 Posted January 9, 2004 Whoa, trying to connect physiology (aging) and physics (time). The planet's velocitys are constantly changing (changing direction) so they are accelerating. You all are talking planetary speed. Picky? yeah. I will try to find the article, but some physicists at Stanford reportedly had an electron arrive at a target before the EM Radiation did, therefore a mass traveled faster than the speed of light. A photon has no mass. Lunch just ended gotta go. I'll be back. Quote
Thinker Posted January 9, 2004 Posted January 9, 2004 Centripital Force is inward, but there most certainly is a force acting outward. Centrifugal Force, or the tendancy of the planet to escape it's orbit definately exists, and is the same as it's Centripital Force. That is why the planet stays in it's orbit. There is no outward acting force. The force of a simple orbiting body has 1 component if it is orbiting at a constant velocity. That force is the centripital force, directed toward the center of the orbit. If a force is applied the body will accelerate in the direction of the force, whether that's toward or away from the center of the orbit. A force can act to accelerate the body, and in that case the body can (but not always) escape the orbit. If there were a constant force acting outward (180 degrees away from the direction of the centripital force), the body would accelerate away from the center of the orbit and likely jump orbit. Quote
lummox Posted January 9, 2004 Posted January 9, 2004 i dont have the tools to enter this argument but i will add that chevy is better than ford Quote
catbirdseat Posted January 9, 2004 Posted January 9, 2004 Except Ducknut is moving away from wirlwind, according to wirlwind, and time has slowed for Ducknut, from wirlwind's frame of reference, not for wirlwind. So which one has aged more than the other? The one who is accelerating is the one which for which time passes more slowly relative to the stationary one. Wirlwind is accelerating because he has some sort of fusion drive under his butt. Ducknut does not. Thus Ducknut ages faster than wrlwind. wirlwind DOES NOT MOVE. It is Ducknut that moves away from wirlwind. The two cases are equivalent, and thus the PARADOX. There is no paradox. Motion is irrelavant. Acceleration is all that matters. Wrlwind knows he is accelerating because he can feel it. Likewise Ducknut knows he is not accelerating. Quote
Sabertooth Posted January 9, 2004 Posted January 9, 2004 (edited) Catbird...think about that for a second. Who says the planets travel at the same velocity? This is true. A planet's velocity depends upon several factors. 1. The sun's mass 2. The planet's mass 3. The distance between them. It rotates at a speed where there is a neutralization of angular momentum. The outward force is based upon the planets mass and the speed it is rotating at. The inward force is based upon the equation F=G*M*m/r^2, where G is the universal constant 6.67 X 10^-11 NM^2/kg^2, M is the mass of the sun in kg, m is the mass of the planet is kg, and r is the distance between them in meters. Incorrect. The mass of the sun has no effect on it's orbital velocity. Only the mass of the orbiting object and the radius of the orbit have an effect on orbital velocity. The inward acting force (centripetal):M plannet*(v^2/r) "Outward acting force"??? This is commonly called "centrifugal force", and doesn't exist. There is no outward acting force on an object travelling with uniform circular(or satellite) motion. Got notes, fixed mistakes!! You are right about the sun's mass, now that I think about it. Centripital Force is inward, but there most certainly is a force acting outward. Centrifugal Force, or the tendancy of the planet to escape it's orbit definately exists, and is the same as it's Centripital Force. That is why the planet stays in it's orbit. Wrong. F=m*a. There is not outward acceleration, therefore there is no outward acting force. For example, take a mass on a string, with the mass moving with uniform circular motion about some center. The string exerts the centripetal force. Cut the string, and the mass will travel at a tangent to the circle. If there were an outward acting force, the mass would leave its orbit at some outward angle. This does not happen. The Centrifugal Force is a MISCONCEPTION. I get it now. Thinker post's cleared it up. How the heck did I get an A in Physics? Edited January 9, 2004 by Sabertooth Quote
Doctorb Posted January 9, 2004 Posted January 9, 2004 Except Ducknut is moving away from wirlwind, according to wirlwind, and time has slowed for Ducknut, from wirlwind's frame of reference, not for wirlwind. So which one has aged more than the other? The one who is accelerating is the one which for which time passes more slowly relative to the stationary one. Wirlwind is accelerating because he has some sort of fusion drive under his butt. Ducknut does not. Thus Ducknut ages faster than wrlwind. wirlwind DOES NOT MOVE. It is Ducknut that moves away from wirlwind. The two cases are equivalent, and thus the PARADOX. There is no paradox. Motion is irrelavant. Acceleration is all that matters. Wrlwind knows he is accelerating because he can feel it. Likewise Ducknut knows he is not accelerating. There is no way to differentiate between acceleration and gravity. That's Big E's "Equivalence Principle". wirlwind cannot conclude whether what he is feeling is caused by an acceleration or from a gravitational force. Quote
Doctorb Posted January 9, 2004 Posted January 9, 2004 Catbird...think about that for a second. Who says the planets travel at the same velocity? This is true. A planet's velocity depends upon several factors. 1. The sun's mass 2. The planet's mass 3. The distance between them. It rotates at a speed where there is a neutralization of angular momentum. The outward force is based upon the planets mass and the speed it is rotating at. The inward force is based upon the equation F=G*M*m/r^2, where G is the universal constant 6.67 X 10^-11 NM^2/kg^2, M is the mass of the sun in kg, m is the mass of the planet is kg, and r is the distance between them in meters. Incorrect. The mass of the sun has no effect on it's orbital velocity. Only the mass of the orbiting object and the radius of the orbit have an effect on orbital velocity. The inward acting force (centripetal):M plannet*(v^2/r) "Outward acting force"??? This is commonly called "centrifugal force", and doesn't exist. There is no outward acting force on an object travelling with uniform circular(or satellite) motion. Got notes, fixed mistakes!! You are right about the sun's mass, now that I think about it. Centripital Force is inward, but there most certainly is a force acting outward. Centrifugal Force, or the tendancy of the planet to escape it's orbit definately exists, and is the same as it's Centripital Force. That is why the planet stays in it's orbit. Wrong. F=m*a. There is not outward acceleration, therefore there is no outward acting force. For example, take a mass on a string, with the mass moving with uniform circular motion about some center. The string exerts the centripetal force. Cut the string, and the mass will travel at a tangent to the circle. If there were an outward acting force, the mass would leave its orbit at some outward angle. This does not happen. The Centrifugal Force is a MISCONCEPTION. I get it now. Thinker post's cleared it up. How the heck did I get an A in Physics? The tension on the string is caused by the MASS of the object. The object has mass (inertia) and its inertia, its resistance to a change in motion, keeps the string taught. Quote
catbirdseat Posted January 9, 2004 Posted January 9, 2004 Huh? That makes no sense. There has to be a conservation of force and momentum. What is opposing the Centripital Force then? If there was no force outward, then there would be no force on the string. When you rotate a ball on a string around you, the string is taught. That is the outward force...The force on an orbiting body acts as right angles to its motion, hence there is no change in its momentum (mv). Quote
Mr._Natural Posted January 9, 2004 Posted January 9, 2004 dr. nick, if f=m*a, than the tension on the string (f?) would be equal at any speed (rpm) as long as speed remains constant? Quote
Stonehead Posted January 9, 2004 Posted January 9, 2004 (edited) Huh? That makes no sense. There has to be a conservation of force and momentum. What is opposing the Centripital Force then? If there was no force outward, then there would be no force on the string. When you rotate a ball on a string around you, the string is taught. That is the outward force...The force on an orbiting body acts as right angles to its motion, hence there is no change in its momentum (mv). Can ya slingshot toward a black hole? Edited January 9, 2004 by Stonehead Quote
Dru Posted January 9, 2004 Posted January 9, 2004 we are all gonna die from gamma ray supernovae Quote
iain Posted January 9, 2004 Posted January 9, 2004 I seem to remember an experiment at the usno where they put an atomic clock on a plane and did a bunch of air travel, then compared it to a clock that remained at the observatory and there was a measurable shift. As you go faster, time slows to compensate for the constant speed of light. This is the explanation for that famous paradox of looking into a mirror while riding a train. Since light has a fixed speed, it can't go faster than the speed of light plus the speed of the train, so you shouldn't be able to see yourself in the mirror. So, something has to compensate, and that is time. Or something like that. Quote
Stonehead Posted January 9, 2004 Posted January 9, 2004 we are all gonna die from gamma ray supernovae Cheney will survive in his underground lair with his bevy of honeys. With anti-aging drugs and stem cell transplants. Quote
Thinker Posted January 9, 2004 Posted January 9, 2004 dr. nick, if f=m*a, than the tension on the string (f?) would be equal at any speed (rpm) as long as speed remains constant? I'll take a stab at this off the top of my head. NO. rpm equates to angular velocity, not the 'straight line' velocity of an object in orbit. The centripital force actually creates an acceleration of the body, i.e. it changes the direction of the body. For instance, if the ball being swung in a circle on a string were to have it's string cut, the ball would tend to travel in a straight line (given no earth gravity effects). Thus, the string is changing the direction (accelerating the body) constantly. The tension in the string is equivalent to the force changing the direction, which is the centripital force. Given a higher RPM, there's also a higher 'straight line' velocity that has to be overcome by the tension in the string. In other words, f=ma, and a higher rpm requires a greater force to maintain the equivalent centripital acceleration. Quote
whirlwind Posted January 9, 2004 Posted January 9, 2004 a photon is measurable isn't it, ie the speed of light. how do you measure something with no mass? even if the number is extremly small it still exisits. and CF does exist or else the planets would spiral closer to, and eventualy hit the sun Quote
Dru Posted January 9, 2004 Posted January 9, 2004 I seem to remember an experiment at the usno where they put an atomic clock on a plane and did a bunch of air travel, then compared it to a clock that remained at the observatory and there was a measurable shift. As you go faster, time slows to compensate for the constant speed of light. This is the explanation for that famous paradox of looking into a mirror while riding a train. Since light has a fixed speed, it can't go faster than the speed of light plus the speed of the train, so you shouldn't be able to see yourself in the mirror. So, something has to compensate, and that is time. Or something like that. trains that travel at lightspeed have been banned by EU directive 4306489 fo reasons of workplace safety, environmental protection, and complaints from railway workers' union. Quote
Doctorb Posted January 9, 2004 Posted January 9, 2004 dr. nick, if f=m*a, than the tension on the string (f?) would be equal at any speed (rpm) as long as speed remains constant? No. F=ma. F centripetal = m object * a centripetal a cent=v^2/r So... F cent = m* v^2/r. So, as v increases, F cent increases. (How do you use subscripts around here???) Quote
iain Posted January 9, 2004 Posted January 9, 2004 as far as I can tell, passenger trains moving over 5mph have been banned in the USA. Quote
whirlwind Posted January 9, 2004 Posted January 9, 2004 cutting the string is the eqivalent to "turning off" gravity, which would allow the object at hand to leave orbit Quote
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