## Investigating value of g just bouncing ideas

### Fightstar

Posted 06 January 2006 - 02:11 PM

So I decided to go for a fairly straight forward investigation this year, and was just wondering who else is investigating 'g' and what experiments they plan to do?

I think the two most interesting ideas I have so far are;
* SHM using various springs and
* Pendulums with the formula g=(4.pie squared.l)/Tsquared

There are a few other ideas, such as simply dropping objects through light gates, but they aren't very original. If anybody knows any good sites for finding out more about this, please post.

Cheers

### waitingforan_alibi

Posted 06 January 2006 - 03:12 PM

i m doing the same investigation. i have 5 experiments:-

- the simple pendulum
- the compound pendulum
- the Kater pendulum (thats a lot of pendulum for one investigation)
- object on a slope ( a= g.sin theta)
- the canvendish-boys experiment to find "G" and then use g= GM/r

### broughy

Posted 11 January 2006 - 10:57 PM

kater's pendulum is a good one - gets you a really accurate result

### dfx

Posted 12 January 2006 - 05:14 PM

Not too original but how about dropping a ball which is electromagnetically held in the air - you know the classic setup for free fall - and then having a motion sensor sense the motion lol.

### Vixus

Posted 16 January 2006 - 04:21 PM

QUOTE(dfx @ Jan 12 2006, 05:14 PM)
Not too original but how about dropping a ball which is electromagnetically held in the air - you know the classic setup for free fall - and then having a motion sensor sense the motion lol.

I don't know about that one-- they may deem it as 'Standard Grade' and let it fail. 5 experiments for finding G?! Wow. Do you need that many? I've got two experiments for my friction experiment, and that's it. Mine seems inferior now. How successful are friction experiments, generally?

### Fightstar

Posted 16 January 2006 - 11:45 PM

Yeh, at least with 5 you have loads of options. I was just wondering if you had the eqipment to do the cavendish-boys experiment? It seems very delicate for a classroom practical. Good luck though.

I did my first experiment today, it was pretty simple but didnt give good results;

SHM with a spring, where g=x4(pie squared)/period squared

x was the stretch of the spring when a mass was added.

Got 8.7m/s/s, so got to find some errors.

### Vixus

Posted 18 January 2006 - 04:17 PM

Obviously you won't get it perfect to 1 d.p. but uncertainties would help.

### Jason Bourne

Posted 19 January 2006 - 11:59 AM

QUOTE(Vixus @ Jan 18 2006, 04:17 PM)
Obviously you won't get it perfect to 1 d.p. but uncertainties would help.

Ok

I haven't started my AH Phys investigation. I thought about doing the usuall determine g through various methods but was wondering if there is anything else that is really cool.