Maybe this is too simple 4 u guyz

1. Feb 28, 2004

BrianT

but we get off homework for 3 weeks if 1 of us gets the answer by 9 am on Monday! yippeee

A mass of 10kg lies on a smooth plane which is inclined at xº to the horizontal. The mass is 5m from top measured along the plane. One end of a light inextensible string is attached to the mass. The string passes up the line of greatest slope and over a smooth pulley fixed at the top of the plane. The other end is attached to a freely suspended 15kg mass. This mass is 4m above the floor. The system is released from rest, and the string first goes slack 1 and 3/7 seconds later

Find the volume of xº

any help will be greatly accepted!!
Thanks

Brian

2. Feb 28, 2004

As for the question: Huh? Volume of x0?

As for whether or not anybody should answer the question: What do you have against homework? It's either do homework or do crappy on exams and have to do extra work to make-up the grade, no?

3. Feb 29, 2004

BrianT

Maybe you dont see it that way when youre 13 and the whole class is to get off -not just you=

But thanks anyway -Cool site, hopefully I'll be back again (when I get all my homework done heheeee

Cheers

BrianT

4. Feb 29, 2004

Zurtex

Well I'm not just going to answer someones homework unless I can IM them and get them to work it out step by step.

However here is a nice Website: http://www.mathsnet.net/ for maths help.

I do believe the sort of examples of questions that you want will be somewhere in this section: http://www.mathsnet.net/asa2/modules/m1.html

Also I think you mean the angle of x, not the volume.

5. Feb 29, 2004

BrianT

Thnaks for those links! Much appreciated.

Just to clear up one thing.

- This test was NOT HOMEWORK - I do that myself all the time.

This was a question way ahead of what we are doing in school - which the teacher gave us on Friday.

and He said that if the right answer was in by Monday Morning - The whole class would get off Home work for 3 weeks

So my guess is that it must be a trick question cos that could never happen.

So I thought i'd ask you guys.

I'm in Derry in Ireland by the way and really say thanks for the answers

6. Feb 29, 2004

Wooh

By the volume of x0 do you mean the angle? If so, after I finish my own hw I will put my hand to it, shouldn't be too hard.

7. Feb 29, 2004

BrianT

Well i wrote it down a volume - but clearly it has to be angle/degree

Thnaks

I will check in - in the morning b4 school

but no worries if ya can't - and mega thanks for even replying

go raibh míle maith agaibh

to you and all

8. Feb 29, 2004

Wooh

Refer to the diagram where needed.
T-10gsinx=10a
T-15g=-15a
T=10gsinx+10a
T=15g-15a
10gsinx+10a=15g-15a
sinx=(15g-15a-10a)/(10g)

an aside to find a
t=10/7
4=at^2/2
8/t^2=a
a=8/(100/49)
a=98/25
plug a in

sinx=(15(9.8)-15(98/25)-10(98/25))/(10(9.8))
sinx=1/2
x=30 degrees

And that is the answer I got: 30 degrees

I did the work quickly though and there is a possibility I made a mistake, but with an answer that nice when taking into account 9.8 m/s^2 for gravity, I heartily doubt that I did

If you have any questions about how I got it, just ask.

edit: the diagram I made (a crappy one, though) was too large to attach. I merely made a right triangle of angle x, with a pulley at the other angle, the two attached blocks (the only important distance being the one block's 4 meters) and noted that only a portion of gravity pulls on the block.
And btw, since no information about it was given, I ignored all forms of resistance, and angular momentum.

Last edited: Feb 29, 2004
9. Feb 29, 2004

Wooh

depends how proficient you are :) (in this case he should probably do his homework though)

10. Feb 29, 2004

Typically, the people that want to get out of homework are the ones that need it the most.

11. Mar 1, 2004

BrianT

Just wanna say a sincere THANK YOU to Wooh for taking thetime and effort to reply.

You are a 'star'. Thanks again

cookiemonster got the wrong end of the stick entirely and obviuosly did not read correctly the earlier posts and sadly seemed a little bitter and the end of it all.

all should have the generocity of spirit of Wooh.

life is too short...

12. Mar 1, 2004

Wooh

Did you get it correct? Did he accept? That's good, but I hope you understand HOW I did the problem, and you should still prep for tests!
As far as cookie goes, his point is a good one! Don't be naive, studying is important, and, especially as you gravitate closer towards your college experience, homework will become more about preparation than menial tasks which yield menial grades. You are doing him a disservice if you think he was meanspirited, more I think he simply meant that the kinds of people who most want to avoid homework, are the ones who could benefit from a bit of studying, but IMHO that is your choice to make, and if you DO blow the next 3 weeks because of this, learn from him! But I sincerely doubt that will happen, so kudos, understand the problem, and succeed.

13. Mar 1, 2004

It's nice when other people will defend you for you. Saves all sorts of work.

Thanks, Wooh.