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Everything posted by spunnery

  1. In any case ,the runner is having a momentum(even if he stands still)equal to that of the spin of earth.in other words,he is moving back with a velocity equal to the spin of earth.So no runner can run faster ,if he ran in opposite direction of earths spin.if you watch the runners from space,you will see the runners running forward,but they are moving backwards,together with earth,Only their relative position with the ground below have been changed.
  2. Sketch2 and sketch 3 are describing two different cases.sketch 2 is the case ,where there is no movement of ship.Sketch 3 is the case if there is movement.if observed time (from B) ,for both the clocks at A and C are same,the result shows that there is no motion of ship.(this is considering that light is travelling at constant speed) On the other hand,if light is travelling at a relative speed with source,even if ship is moving,the clocks will show same time. so either one can be true.
  3. Sorry,I am discussing now about post#12.I made a bad notation A',B',C',which is confusing you.A',B'and C' are the position of A,B and C respectively ,before 't' seconds.please see both are same frame only-sorry again
  4. Please note that i mensioned the time delay,as observed from point B.but actual time at all the three points remain same(there is no time delay).And for the mathematical part,it is clear that i assume the first postulate of SR-light appear to be travel at constant speed for any observer-(i.e,velocity of light is not affected by the velocity of source).So first agree with sketches (if don't tell me why?) remaining calculations are simple mathematics only.please go through it again and tell me preciselly in which step ,i have made a mistake. As per my argument,no time delay due to change in velocity,so there is no point in arguing about the time delay due to rotational velocity. A delay willbe observed,which is equivalent to the time taken for the light reflected fromm the needle of clock ,to reach a far away observer-Analogy -a far away star we see now is a star of past. Appologise for harsh meanings,if any for my sentences-i am not good enough in english language.
  5. My first request is ,not to see the problem with a prejudice.secondly,special relativity and general relativity itself are result of thought experiments,which have to be proved yet (atleast a non negligible percentage beleive so). Again ,the word gedanken,literally means as 'thought',in german language.Which you are telling ,will show me,how SR works.So a gedanken experiment is quite enough to falsify it also. finally,the experiment i mentioned can be done practically on a small space ship,by reflecting,the lights to travel a considerable distance, using mirrors fixed at an angle to the side walls of ship.
  6. Sorry for delay.and sorry for a useless attachment.Here are some interesting stuff on the subject.(please refer sketches) Consider you are in a space ship.Say it is 300,000km long(For the experiment ,it is not mandatory to be the length of ship to be that much.You can deflect the path of light using mirrors to achieve desired length). Refer the sketches in attachment. Synchronise three clocks from position A take one clock to position B midway and another to position C (front end)motion is considered to be in AC direction. Now see the sketch 2,if there is no motion,as observed from B,you will see the clocks at A and C showing a time of T-0.5 seconds with respect to B's clock.(150,000/300,000=0.5). Now see sketch 3. it is self explanatory .is it interesting? if the light is travelling at constant speed,this will be the result. if so ,this is an experiment which can be done from an inertial frame ,to show that frame is moving at a constant velocity,u. Otherwise,special relativity is flawed. Correct me,if i am wrong.? LIGHT.pdf
  7. if the length is really shortened,that is the answer for cancellation of time dilation,in a longitudinal clock.no need to derivate the whole formula.otherwise,i will just derive it here,correct me if i am wrong? the total horizontal distance travelled by clock = vt distance travelled by reflector when the light ray from sorce hit mirror = vt/2. total length of forward path of ray = h(distance between source and mirror)+(vt/2). total distance travelled by ray in backward path will be = h -(vt/2) Hence total distance travelled by ray will be '2h'.which is same for a clock at rest.But, h'(total path) for perpendicular moving clock is 2 multitplied by sqrt of [(vt)^2 + h^2] So it is clear that ,no time dilation in the case of longitudinal clock.this is the other side of the reason why length contraction happening only in the direction of motion.
  8. In time dilation,the rate of clock is changed -because the path of light(and distance increasaed) is changed.This is very clear from the derivation of time dilation using pythogorus theorom(I know the lorentz transform derivation is more complicated).In the above derivation if you keep the clock horizontal(ie, instead of prependicular to the motion,you keep clock parallel to the direction of V),you can see the effect of V is nullified(please imagine the total path of light).means clock is running at a same rate as if it was at a rest frame.Does it means,for time dilation ,to occur you have to keep the clock perpendicular to motion Same in the case of length contraction also,in a moving frame,if you use a ruler to measure length,the ruler also is subjected to the shorteneing (in appearance)and finally you will measure the same distance.But if you try to measure a distance in a moving frame,from a frame at rest,of course it will appear to you that distance is shortened.this is only observation and the true thing is distance remains same.No shortening
  9. By vertically ,i mean perpendicular to direction of motion.Could you please explain me regarding the laser thing(i appologise ,i am only playing with some basics) Anyhow i will try to explain my point again. Two synchronised clocks are kept 300,000 km apart in a straight line at A and B.Observers at A & B will see each others clocks are one second behind their time.[time taken by the light (velocity is approximate only)to travel from A to B and vice versa].Now consider A is travelling with his clock towards B upto C (150,000 km.from A)No matter what speed A is going,When he reach C he will find now B's clock is only half second behind him.For A ,B's clock appears running faster while he is travelling and vice versa. A's speed will only change the rate of change in B's clock from 1 second lag to half second lag.So basically the result depends on the position of A at the instance. Consider that both are travelling towards each other and with high velocity.things become more complex . Here relative position at the instance is more important to get in to a conclusion about the results on observervations made by both A and B .But you will see that at any instance,the time elapsed by both clocks are same.So my argument is that use Lorentz transform to obtain the results.but the spacetime curvature and time dilations are only the observations but not the results.
  10. of course the ball is horizontally at rest in his reference frame(this is actual position),but he is not seeing it .he will see the ball at a position where ball was before 't' seconds ,depending on his speed.Is lorentz transforms are the complex version of the situation ?Note that a correction is required to find the exact position ,from the observed position.
  11. some imaginations. Me and my friends were travelling in a rocket with a constant velocity towards a planet.nobody except me knows that rocket was travelling towards planet.There was no background stars or anything in the sky visible through the front glass,to make us aware of the motion. My friend A told me "see it is a special kind of planet .it is expanding" B told me "A is wrong,That planet is moving towards us". C told me "no no we are moving towards the planet". How can you say A is wrong?.Only because i know the rocket is moving towards the planet .But can i say A is completely wrong ? No.Even we are moving towards and if planet is expanding as well,we will see the same scenario.To say A is absolutely wrong,I need more datas like distance ,diameter of planet,velocity of rocket etc. If we know the rocket is at rest,then either A or B or both of them are correct. What i want to say is that in such problems, before coming to any conclusion about what you have observed,you have to put in consideration with all other datas , the relative position and movement of the observer. Relative position of the observer ,can cause a major difference in observations made.So you have to make proper corrections to the equations ,instead of thinking wild about a warped spacetime. A simple example, A man throws up a ball vertically from a ship moving at a constant velocity.if he is moving at a small velocity compared to that of velocity of light.For him ,the position of ball is always vertically above his head.This is because the horizontal velocity of ball and ships velocity is same.Finally fo him, the ball will reach back to his hand after executing a vertical path. What happens,if the ship is moving at a velocity,nearer to that of light.this time also,the balls position will be always vertically above his head as before and because of same reason.Butin this case, before the light reflected from ball,reach him,he will move ahead horizontally to a new position ,where the light pulse will reach him. So he will see the ball at an angle behind him.Finally he willl observe that the the ball is taking an inclined path backwards and coming back to his hand through an inclined path. From this,if the observer deduce that if he throw a ball vertically up,it will move up in an inclined path,it will be total blunder.So what he can do is to give proper corrections to the equation to make the path straight.And this is in true the position of ball. I explained all this because,i want to say that what Lorentz transformation is doing ,is only the necessary corrections to the observations,considering the relative movement and position,of the observer. There is no such time dilation or length contraction,but only necessary correction according to the relative position and movement of observer taken in to consideration. Anything more interesting?
  12. Thank you .(and incidentally can also have sideways motion but this does not contribute).This was the answer i was looking for.Sorry for the ignorance in the subject.
  13. Answer not seems to be specific to my question.(may be my question is not clear).The acceleration of expansion of universe is calculated from the doppler shift of spectrum of radio waves emitted from the galaxy.Do we give any consideration (or say correction)for the direction of motion of galaxy with respect to earth(or in general say with respect to our galaxy).And if not doing so,does it make huge errors.
  14. Could anybody who is familiiar help me with some details of doppler red shift? In the calculation for velocity of an object(say galaxy) ,do we consider the direction of motion of body.I will explain Object receding will form a red shift. Object approaching will form a blue shift. What about an object moving at an angle with the observer.Of course the value of shifting will be different. Do we give any consideration for this while calculating velocity? for example, If the observer is at right angle to the direction of object,he will recieve signals without a shift????
  15. So why the paradox,Inspector chasing the light at .99c observe the light travelling at c?.This can be happen only if source of light is also moving at 0.99c,Otherwise he will observe the light with just 0.01c (same as the difference between the ball dropped from bridge and ball dropped from inside the train).Correct me ,if i am wrong? Otherwise in general ,we can say all the physical constants remain same to any inertial observer
  16. Issue is that physical laws are not changed in any frame.How comes light can break the law(to be constant to all observers)?.Why the simple logic in this problem not applicable to light?Does any physical laws are changing when you travel at a speed nearer to light?.I think only thing is you have to rewrite the formulas according to the position (space co-ordinate at the instance)of the observer.
  17. Ok i agree.Shall i try to say with one example,that accelerating frames are also inertial frames.But only thing is that we have to make corrections to the results,considering the aceeleration.for example; Case1 - train is moving at a constant speed. A person inside the train dropped a ball verticaly down.At the instance he dropped the ball,both ball and train have same horizontal velocity.Gravity pull the ball down.Resultant of the horizontal velocity and vertical gravity will bring the ball through the diognal of paralellogram,.In the mean time floor of train (with the person)will travel equal horizontal distance,as ball has travelled.So the ball will hit the floor of train verticaly down the person,since the final position of the person is changed. Case-2 -the train is moving at an acceleration. The ball dropped,in this case will have the velocity ,V1 of the train at that instance(inertia?).Now the ball will travel through the diognal of parralellogram drawn with v1 and gravity.but the train ,is acellerating(it will have a greater velocity and will be displaced horizontaly more,with respect to the ball).The floor and person will move little further than the point (depending on rate of acceleration)where ball will hit the floor.So the observer will see the ball hit the floor behind him(and this is true).Does any physical laws changed here?.only thing is you have to give appropriate value to the final position of the person(observer).
  18. consider a train moving at a constant velocity. let the top of the train be open.drop a ball verticaly to the train from a bridge ,while train is crossing the bridge.What will be the path ball.Again drop the ball when the train is stopped below bridge. In both cases the ball will hit the floor of train at different places.Can it be considered as a physical experiment showing different results of same experiment for a body at rest and a body moving at a constant velocity? Now can we call the moving train as an inertial frame.
  19. Sorry I was not aware about that.really sorry
  20. The first answer is 31.709 m /sec. Second answer is 257.719 km
  21. Did you say i am right or wrong? I couldn't get what you mean.
  22. Gravity of course!.The person standing on the platform will see th ball on the train falling slower? Never .He will see a different path for the ball ,instead
  23. Sorry i was late on the subject.Here i am twisting little and i would like to ask you to explain some mathematics about the travelling train. The same old experiment(tired?).Consider a train moving with a uniform velocity 'V' and you are standing inside the train.Now you are dropping a ball of mass 'm' from a height 'h'.You will see the ball dropping vertically down to the floor of train . The same result will happen if you do it on the platform also. I would like to hear from you ,why this is happening so?I am looking for some mathematical explanation rather than the terms Inertia ,parabolic path etc,etc.
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