#1

ive been trying to work out this problem forEVER, and i cannot figure it out. its from a homework set online, so each time i submit an answer and it's wrong, the numbers change and i get to try again. but yeah, its either worded terribly or im just missing something really obvious:

Because Earth's rotation is gradually slowing, the length of each day increases: The day at the end of 1.0 century is 1.0 ms longer than the day at the start of the century. In 50 centuries, what is the total (in hours) of the daily increases in time (that is, the sum of the gain on the first day, the gain on the second day, etc.)?

thanks guys

EDIT: nevermind, i finally got it. so dont bother trying to figure it out if youre just reading this now. i would just delete the thread now, but i figured there'd be some people interested in the answer.

which is 12.6736.

alll the help was much appreciated. thanks everyone!

Because Earth's rotation is gradually slowing, the length of each day increases: The day at the end of 1.0 century is 1.0 ms longer than the day at the start of the century. In 50 centuries, what is the total (in hours) of the daily increases in time (that is, the sum of the gain on the first day, the gain on the second day, etc.)?

thanks guys

EDIT: nevermind, i finally got it. so dont bother trying to figure it out if youre just reading this now. i would just delete the thread now, but i figured there'd be some people interested in the answer.

which is 12.6736.

alll the help was much appreciated. thanks everyone!

*Last edited by popapez at Sep 4, 2007,*

#2

ahhh school starts tomorrow...

#3

I'm feel little a stoned right now, but I probably couldn't help you anyway if I was feeling myself as I'm ****e at maths . Sorry.

#4

That question is worded horribly.

#5

I'll have my secretary browse over it.

It's a little too low-brow for me, I'm afraid.

You know how they saying goes; maths is for pure benders. Allegedly.

It's a little too low-brow for me, I'm afraid.

You know how they saying goes; maths is for pure benders. Allegedly.

#6

If i understand it correctly, you have to add the numbers, from 1-50 in sequence.

eg, 1+2+3+4.....

But that's just to start with.

I think.

eg, 1+2+3+4.....

But that's just to start with.

I think.

#7

i would say 50 ms.. but maybe im missing something too

#8

I think each day is (1/365)ms longer than the day before. So then multiply that by 5000 years worth of days (can't be bothered to work out leap years etc.) And convert to hours.

#9

Yeah, I think this is like a permutation kind of thing. Like 1+2+3...+50=answer?

#10

If i understand it correctly, you have to add the numbers, from 1-50 in sequence.

eg, 1+2+3+4.....

But that's just to start with.

I think.

yeah, which would be 1275. multiply that by 1 ms, and convert it to hours, right?

well, ive tried that and its not correct. any other ideas?

#11

21.25 hours ?

Edit: No wait, that's not right

Edit 2: .....or is it?

Edit 3: ....nope, guess not

Edit: No wait, that's not right

Edit 2: .....or is it?

Edit 3: ....nope, guess not

*Last edited by yogurt_overdose at Sep 4, 2007,*

#12

I think each day is (1/365)ms longer than the day before. So then multiply that by 5000 years worth of days (can't be bothered to work out leap years etc.) And convert to hours.

wait, you think that it says that each DAY increases by one ms? because im interpreting it as each century increasing by one ms...

#13

i think the answer is 0.00039194444444444444 Hours

#14

i think the answer is 0.00039194444444444444 Hours

tried it, thats wrong

#15

How about .02125?

#16

nope.21.25 hours ?

Edit: No wait, that's not right

Edit 2: .....or is it?

#17

How about .02125?

nope

#18

12.7 hours?

#19

How about 8.333(nonterminating decimal)*10^(-4)?

#20

^ no and no lol.

i appreciate the help guys

i appreciate the help guys

#21

We have to be missing something here...

#22

We have to be missing something here...

yeah, tell me about it..... this question is retarded.

heres the hint it gives me: How many days are in a year? How many years are in the given time period?

but i dont see how that is very helpful at all...

#23

The answer is: because god made it so stop questioning his logic.

#24

Is it .0000138?

Just a guess. Also have you tried entering all these answers as fractions? Maybe that's what it wants.

Just a guess. Also have you tried entering all these answers as fractions? Maybe that's what it wants.

#25

Okay, so there are 1,826,250 days in 50 centuries I think... Because we say 365*100=36,500, then take into account the leap years with one extra day and in a century there are 25 (100/4=25), so you have to add 25 days to your previous total. That gives you 36,525 for the century. Then multiply it by 50 and you get 1,826,250. So there is your total amount of days I believe, hope this is a start on something, I'm posting now so other people can work on this and check my math as I am.

#26

Because Earth's rotation is gradually slowing, the length of each day increases: The day at the end of 1.0 century is 1.0 ms longer than the day at the start of the century. In 50 centuries, what is the total (in hours) of the daily increases in time (that is, the sum of the gain on the first day, the gain on the second day, etc.)?

Awfully worded question

So, in one century the length of an Earth day increased by 1.0ms. Therefore in 36500 days the length increases by 1.0ms. But this is where I think we need a bit more info. If the increases are following some kind of sequence then we could use the formula for the sum of an arithmetic/geometric sequence, but we don't know that.

Im gonna have an absolute stab in the dark and say 0.05 seconds, but surely it's not that easy haha.

Sorry I can't be more helpful.

Awfully worded question

So, in one century the length of an Earth day increased by 1.0ms. Therefore in 36500 days the length increases by 1.0ms. But this is where I think we need a bit more info. If the increases are following some kind of sequence then we could use the formula for the sum of an arithmetic/geometric sequence, but we don't know that.

Im gonna have an absolute stab in the dark and say 0.05 seconds, but surely it's not that easy haha.

Sorry I can't be more helpful.

#27

Is it .0000138?

Just a guess. Also have you tried entering all these answers as fractions? Maybe that's what it wants.

wrong. and it wont let you enter anything as a fraction.

#28

How about 3.541666(non-terminating)*10^(-4)? I think that converts to .0003541666(non-term.)

#29

nope...

#30

1.39e-5?

If the earth gains 1.0 ms per century, wouldn't it gain 50.0 ms over 50 centuries? So then convert that to hours. That's how I got that answer.

EDIT: Nevermind, that's already been tried...

EDIT 2: These internet assignment sets are a pain in the ass. I'm getting ready to do one for physics right now. The one I'm working with sometimes doesn't think the right answer is correct. I've even entered the right answer with the right significant figures, had it rejected, entered the right answer with the wrong significant figures, and had it say "that's right, but you should have said with this number of significant figures" and it was what I put in the first time. Good Luck!

If the earth gains 1.0 ms per century, wouldn't it gain 50.0 ms over 50 centuries? So then convert that to hours. That's how I got that answer.

EDIT: Nevermind, that's already been tried...

EDIT 2: These internet assignment sets are a pain in the ass. I'm getting ready to do one for physics right now. The one I'm working with sometimes doesn't think the right answer is correct. I've even entered the right answer with the right significant figures, had it rejected, entered the right answer with the wrong significant figures, and had it say "that's right, but you should have said with this number of significant figures" and it was what I put in the first time. Good Luck!

*Last edited by aprescott_27 at Sep 4, 2007,*

#31

theirs no sequence if it had the time after the first

: or yer ^^

0 hours, 0 mins, 0.050 seconds

(if ms is a 100th of a second, which i think it is)

opps ok 1000th= 0.0050 seconds

**and**second century you could work it out the 50th using the "nth term" method, either they forgot to mention another figure or its worded pretty damn badly: or yer ^^

0 hours, 0 mins, 0.050 seconds

(if ms is a 100th of a second, which i think it is)

opps ok 1000th= 0.0050 seconds

*Last edited by O-Clamp at Sep 4, 2007,*

#32

It's a one-thousandth of a second, .001, isn't it?

#33

^^A millisecond is 1000th of a second.

50 ms * (1 s / 1000 ms) = .05 s

50 ms * (1 s / 1000 ms) = .05 s

#34

It's a one-thousandth of a second, .001, isn't it?

yeah

#35

^^A millisecond is 1000th of a second.

50 ms * (1 s / 1000 ms) = .05 s

0.05...??

that would be 500ms then lol

#36

EDIT 2: These internet assignment sets are a pain in the ass. I'm getting ready to do one for physics right now. The one I'm working with sometimes doesn't think the right answer is correct. I've even entered the right answer with the right significant figures, had it rejected, entered the right answer with the wrong significant figures, and had it say "that's right, but you should have said with this number of significant figures" and it was what I put in the first time. Good Luck!

ha, yeah, i know. this one im doing now is for physics, and it does stupid things like that too.

its wileyplus. is that what youre using?

#37

50.0034246575ms or 0.34194 hrs

*Last edited by Attack at Sep 4, 2007,*

#38

No, I'm using Mastering Physics. My ex g/f's physics class uses WileyPlus, though. Had to help her a few times last semester.ha, yeah, i know. this one im doing now is for physics, and it does stupid things like that too.

its wileyplus. is that what youre using?

#39

50.0034246575ms or 0.34194 hrs

nope

#40

Well because you made everyone think it was so hard to solve, I spent too much time calculating while in fact it's the easiest math problem ever. Just learn to read properly.

at the end of 1 century the days are 1.0 ms longer. that means in 50 centuries the days are 50.0 ms longer (=0,5 s)

This problem never said anything about a quadratic increase, so we must assume that the increase is constant.

This would mean you could just divide the ms by the number of days in 1 century, which is 36524 (100×365, and 1 day extra per four years, except on switchings of centuries) which means that the daily increase is 0,0000274 .

divide this by 360000 which is how you convert it to hours, which will make 0,000000000761 hours per day increase, now multiply it by (36524×50) which makes 0,00139 hours per 5000 years.

if you want to write this down into your notebook:

ms = Millisecond

c = Century

d = Day

h = Hour

1ms/c / 36524d = 0,0000274ms/d

0,0000274ms/d / 360000h = 0,000000000761h/d

0,000000000761h/d × (36524d × 50c) =

at the end of 1 century the days are 1.0 ms longer. that means in 50 centuries the days are 50.0 ms longer (=0,5 s)

This problem never said anything about a quadratic increase, so we must assume that the increase is constant.

This would mean you could just divide the ms by the number of days in 1 century, which is 36524 (100×365, and 1 day extra per four years, except on switchings of centuries) which means that the daily increase is 0,0000274 .

divide this by 360000 which is how you convert it to hours, which will make 0,000000000761 hours per day increase, now multiply it by (36524×50) which makes 0,00139 hours per 5000 years.

if you want to write this down into your notebook:

ms = Millisecond

c = Century

d = Day

h = Hour

1ms/c / 36524d = 0,0000274ms/d

0,0000274ms/d / 360000h = 0,000000000761h/d

0,000000000761h/d × (36524d × 50c) =

**0,00139 Hours per 5000 years***Last edited by Stukart at Sep 4, 2007,*

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