Barry's Moving Walkway

[RonPurewal]

if that still doesn't totally make sense, here's an example that is probably more intuitive:

• you get on an upward-moving escalator.
• you're in a hurry to get to the top, so...
• ...you walk up the stairs.

if you understand why walking up an upward-moving escalator will get you to the next floor more quickly, then by extension you also understand the bike/train thing.

[sahilk47]

if that still doesn't totally make sense, here's an example that is probably more intuitive:

• you get on an upward-moving escalator.
• you're in a hurry to get to the top, so...
• ...you walk up the stairs.

if you understand why walking up an upward-moving escalator will get you to the next floor more quickly, then by extension you also understand the bike/train thing.

Got it! Thanks!

[tim]

[RonPurewal]

if that still doesn't totally make sense, here's an example that is probably more intuitive:

• you get on an upward-moving escalator.
• you're in a hurry to get to the top, so...
• ...you walk up the stairs.

if you understand why walking up an upward-moving escalator will get you to the next floor more quickly, then by extension you also understand the bike/train thing.

Got it! Thanks!

you're welcome.

[JohannaH678]

Hi there,

I found this thread very helpful and agree that the alternate strategy of averaging the two speeds to find the speed of Barry relative to flat ground is really helpful.

I read the whole thread but I still have a question on Vikash's post from 2/23/13 where he said:

"Like i said, the total distance for movement both ways is constant and as such the ratio of the time is equal to the inverse ratio of the effective speeds(or relative speed in this case) both ways which is ..."

Am I not connecting the dots here? Is he just rephrasing something else in a different way when he says: 'time is equal to the inverse ratio of the effective speeds'? Or is this just a rule that should be memorized? Can you explain this statement in another way or use it in another example? I don't follow it.

Thanks,
JH

[RonPurewal]

imagine you have to travel some fixed distance.

if you travel that distance at 60 miles per hour, the trip will take you exactly half as long as it would at 30 miles per hour.
speed times 2 ... time divided by 2

more generally
speed times N ... time divided by N
(and vice versa)

i'm pretty sure this is what the "inverse relation" comment is supposed to mean.

[JohannaH678]

Thanks

[RonPurewal]

you're welcome.