You are Here: Home >< Maths

# More SHM watch

1. I have the answer to this. It's 25 N. But I can't get to that answer at all.

Here is the question and my workings on the attachment.

What should I try now? Thanks.
Attached Images
2. Scan0010.pdf (352.0 KB, 58 views)
3. (Original post by maggiehodgson)
I have the answer to this. It's 25 N. But I can't get to that answer at all.

Here is the question and my workings on the attachment.

What should I try now? Thanks.
I also got 25

there is a numerical error somewhere
will now look for it
last line you are missing the 400
4. (Original post by maggiehodgson)
I have the answer to this. It's 25 N. But I can't get to that answer at all.

Here is the question and my workings on the attachment.

What should I try now? Thanks.
On the penultimate line, you have: , you should then expand this to get: , you've left it as

Sorry if the LaTeX doesn't work, I'm on my phone and it's very hard to type.
5. (Original post by TeeEm)
I also got 25

there is a numerical error somewhere
will now look for it
last line you are missing the 400
Yes, the expansion is missing but 400 L x = -100 acc

How does that tell me what Lamda is?? I don't know.
6. (Original post by maggiehodgson)
Yes, the expansion is missing but 400 L x = -100 acc

How does that tell me what Lamda is?? I don't know.
then x double dot = minus 4 lamda
so 4 lamda = 100 (you found it at the top of the page as omega squared)
lamda = 25
7. (Original post by maggiehodgson)
Yes, the expansion is missing but 400 L x = -100 acc

How does that tell me what Lamda is?? I don't know.
In SHM, you have , so in this case, you have

Hence:
8. (Original post by TeeEm)
then x double dot = minus 4 lamda
so 4 lamda = 100 (you found it at the top of the page as omega squared)
lamda = 25
Oh good grief. I see it now that you've pointed it out.

Thanks
9. (Original post by Zacken)
On the penultimate line, you have: , you should then expand this to get: , you've left it as

Sorry if the LaTeX doesn't work, I'm on my phone and it's very hard to type.
Yes , your phone did the trick and so did your response. It makes perfect sense and I'm miffed that I didn't spot it myself.

Thanks again.

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 14, 2016
Today on TSR

How do you think you'll do?

### University open days

Wed, 25 Jul '18
2. University of Buckingham
Wed, 25 Jul '18
3. Bournemouth University
Wed, 1 Aug '18
Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams