martianxx

How long has this forum been going?

I am doing a physics assignment on basic mechanics of a rollercoaster i have written it all up apart from the section on future developments in this area of physics. I was tinking about doing it on space advance since there is alot of mechanics, does anoyone have any other suggestions or knows of somthing quite unique to do with mechanics of free fall that you can refer me too to create a more interesting project?

whats the point in giving a question letting one person have an attempt and then post the answer when they get it wrong, at least let other people have a go and maybe the first person might want to correct themsleves.

if i have a elastic ball and i throw it at a wall on cantact the shape will change but the volume is the same. So if i put a dollar or whatever in the bank when i left went all the way to the star and then came all the way back i could pay for my trip assuming i could live for 720 years.

i heard that gallium was reasonably safe yet you need to take some care and precautions while handleing it. May i ask what you are going to do with the gallium, just interested

If i were doing it i would say what y = when x=0 y would = -3 then what x is when y = 0. You have to use the quadratic formula x = -b (+/-) Root of b^2 - 4ac all divided by 2a for this particular equation a = 2 b = 0 and c = -3 you can work out the maximum/minimum via differentiation but you can get a prety good outline of the graph from working out the y and x values. p.s Remember when you square root in the formula it gives two answers still when b = 0.

I think i have cracked this idea. The body that is moving at a given speed has a time change relative to someone's time who is stationary due to the changes in acceleration and speed etc. Is this correct? If it is does this mean that if i set of in space acceleration at 1 earth gravity per second towards a star 2500 light years away not at but close to the speed of light the time taken for my family on earth is 2500 years but for me it would seem like alot less due to my acceleration and deceleration when i got closer to the star. Is this right? So more like a time dilation rather than a time change.

Sorry, i meant to say moving.

I had a question in a recent exam that asked you to prove the formula to calculate the sum of an A.S. I only got 2/11 on it so i was wondering if someone could tell me it. I have searched the internet for one but all seem to be a bit rubbish and i think i can get better results here

shouldnt h be s for displacement?

How can a light year = distance light travels in a year, if time stops at light speed according to relativity? Surely light could travel 2 lightyears in an instant if it wants...

according to relativity IF it were possible to reach the speed of light time would stop leaving what iNOW said would be correct you can travel anny distance instantly, there would be no time or distance.

going back to the original question i like to look at the data that you have. you have: s (displacement): 140m t (time): 3.6s v (final velocity): 53 ms you can then use s = [(u + v)/2]t 140 = [(u + 53)/2]3.6 140 = [(u/2) + 26.5]3.6 140 = 1.6u + 95.4 44.6 = 1.6u 27.875 = u Then you can use this to work out the acceleration: v = u + at 53 = 27.875 +3.6a 25.125 = 3.6a 6.9792 = a Hope this helps - ps may have made a slip up on the maths in the first part it is late and i am about to go to bed

It is quite hard to understand, this is how i see it. If on car is travelling at 70 mph and another is travelling at 100mph the first car is accellerating away from the second. A person at a stationary point observes the first car travel by and it appears to be going very fast, yet from the drivers seat on the second car the driver sees that the car appears to no be accelerating away as quickly. This is motion relative to time. But if time was relative to motion and its speed changed when a body moves then time would have a speed. So what i as saying is if we give time a speed. 1 being a body in motion at a speed of 186000 miles per second and 0 being a stationary body. When you begin to move from 0 to one time begins to accelerate less quickly from you and so its speed is slightly less. Only if it were possible to travel a speed nesicary of have a great significance to the speed of time would it be possible to prove this of course. In theory when traveling at the speed of light it would be as if the 2 cars were both traveling at exactly 80 mph realivly they would appear to not be moving at all, as if they were stationary. Yet the world around them still moves. deltaT/deltaT would = one assuming that speed had no effect on time. Sorry, it appears that i have just accidently proved relativity. Look here http://www.themodernreligion.com/basic/quran/quran_time.htm where it is explained alot better. just ignore some of the later, it is more related to islam than physics.

no there is a way where you start if assuming that A=B or somrthing, ill find out tommorow.

v = IR you can rearrange to solve all the problems.

I have recently been reading a book called "The fabric of the cosmos" and it states that there is a relationship between speed in time and speed in space. It says that when stationary a body is moving only through time and not through space, seems obvious. Yet when the body begins to move time slows down slightly. It says that when travelling at the speed of light time stops. I was annoyed by the concept of "speed of time" how do we calculate a speed of time. I found out about a group of scientist that took a highly sensitive clock from London Heathrow to Sydney Australia in a Boeing 747. the time taken by the very accurate clock was less than the amount of time that other clocks said. I am not sure if there is already a way to calculate the speed of time, but just in case there isnt i have attempted to make one. I started of by thinking that the speed of time when the body is stationary was 0. And the speed of time when travelling at 186000 miles per second was 1. i then asked my self how fast you would have to travel to have a speed of time of 0.5 this is obvioulsy 186000/2 = 96000 miles per second. I then said that if traveling at 186000 miles per second the speed of time is 1 then it would have to be 186000/186000 = 1 i then took the idea of the speed of light being constant. I worked out that logically the speed of time should be equal to the speed in space divided by the speed of light. If you do this you get a very small number supposing you do it with a possible speed and you get a number that doesnt really mean much. So i developed the idea of the speed of time being how long a second when stationary is when moving at a given speed. The speed in space/speed of light gives the difference between the time of a second while stationary and the time of a second while traveling at the orignal speed. So i said that 1-speed in space/speed of light = time of 1 second while moving. As you can see, when traveling slowly the time changes so little that no one would pick it up, only this amazing clock that went to australia. I will give an example the clock that went to australia if the time taken on a normal clock was 24hrs and the plane averaged 605 mph then: First we must express 605 mph in miles per second. We have to do the calculation, 605/60/60 = 0.168 3sf we put this speed into the equation speed of time = v/c to get, 0.168/186000 = 9.03x10^-7 = 0.000000903 This is the difference in the speed of time so we have to take this from 1. 1 - 0.000000903 = 0.999999097 this is the real time of one second while flying at 605 mph. Assuming it takes 24hrs to get from london to sydney the real time taken = 24x60x60 = 86400. then it is 0.999999097 x 86400 = 86399.92seconds. This in hours is 86399.92/60/60 = 23.99998 so you end up losing 0.8seconds of time. If any of this seems incorrect or has already to your knowlaged been discovered please tell me, i would really like to hear from you.