Anyone good at maths?

stu · 2010-11-22T22:16:17+00:00

Okay heres the story. I wrote my maths matric paper 1 on the 4th (i think) and one of questions has been bugging me ever since. Here it is: Tshepang rushed from home to the soccer stadium at 165km.h to see her favourite team. They lost the game so, feeling sad, she drove home taking the same route, at 110km.h Culculate Tshepangs average speed for the whole trip. It is not 137.5km.h I have tried lots of different methods and ideas to get the answer but Im not wining with this one. Any one have any ideas? I know if I do get the answer Im going to kick myself for not getting it in the exam.

vic

Llewelyn wrote
Alan Ratcliffe wrote Not really, tau becomes more important the closer you get to C, but still has an effect at lower speeds. So I suppose in this case it would depend on how many decimal points you were willing to calculate. ? Hmmm... hadn't even considered L...
Just because I was bored while studying for my physics exam last week, I calculated what my mass would be at 100km/h...the change was so tiny I can't even remember it ?

Correct.... ?

Calculate your mass at say .9 of C (300,000 km/s)....at C, your relativistic mass strives towards infinity ?

AlanRatcliffe

vic wrote Calculate your mass at say .9 of C (300,000 km/s)....at C, your mass strives towards infinity ?

You mean zero don't you? I'm middle-aged, so my mass is striving for infinity already! ?

vic

Alan Ratcliffe wrote
vic wrote Calculate your mass at say .9 of C (300,000 km/s)....at C, your mass strives towards infinity ?
You mean zero don't you? I'm middle-aged, so my mass is striving for infinity already! ?

no, not zero... relativistic mass increases....and the larger the mass, the more a body resists acceleration.....that's why it's (almost) impossible to accelerate a space ship to light speed.... Careful Alan...and you're not even under relativistic acceleration... ?

AlanRatcliffe

Doh! :-[ And that's why light can travel at C - zero mass.

vic

Alan Ratcliffe wrote Doh! :-[ And that's why light can travel at C - zero mass.

Gee..we are derailing a bit.....

No, it's because photons are (considered) massless (0 mass at rest) to start with and thus 0 mass at C ? ..also for them to travel faster than the universal speed limit is forbidden in space-time because then they will go back in time.... ? ...strange universe or is it ?

Check this out

http://wiki.answers.com/Q/Why_do_objects_become_heavier_when_they_approach_the_speed_of_light

Kalcium

What I don't understand is the fact that Raithza had the correct solution from the very first reply and yet there were many incorrect answers followed by a later correct answer by Wizard, and only Wizard gets credit ? just saying... ?

[deleted]

That seems to be the way of online forums, guy. *shrug*

vic

stu wrote Thanks Wizard and raithza.
Raithza what you said makes perfect sense. Im not trying to find the average between the two numbers.

Kicking myself for not thinking of that >☹

@Kalcium...see above

Kalcium

Oh, my bad, didn't see that...I was referring to this post

vic wrote a very elegant solution....Wizard must be a Math wizz kid... ?

but still, my mistake ?

raithza

yes...YES... give me my internets credits... i wants them... ?

aja

raithza wrote yes...YES... give me my internets credits... i wants them... ?

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