Jump to content
Sign in to follow this  

Measuring g

Recommended Posts

Hey guys, i'm doing a Physics design IA, and i need help on how to measure g. The main problem is that i need to know howto do a free fall apparatus in order to measure time with accuracy.

Thank you!

Share this post


Link to post
Share on other sites

you could ask your phsysics teacher about this, I remember we did experiments on gravitational acceleration with a trapdoor apparatus and a ball, when the ball was released it would start measuring and when the ball triggered the trapdoor on the bottom it would stop the time. I dont know if that is dexactly what you are looking for though.

Also if you need an environment of greater height that needs to be away from outside influences (wind rain etc) you could set up in your school gym or possibly in as stairwell (of course at a time that would be convenient regarding usage of the area by other students)

Share this post


Link to post
Share on other sites

you could ask your phsysics teacher about this, I remember we did experiments on gravitational acceleration with a trapdoor apparatus and a ball, when the ball was released it would start measuring and when the ball triggered the trapdoor on the bottom it would stop the time. I dont know if that is dexactly what you are looking for though.

Also if you need an environment of greater height that needs to be away from outside influences (wind rain etc) you could set up in your school gym or possibly in as stairwell (of course at a time that would be convenient regarding usage of the area by other students)

Yeah lol that thing you were saying.

Can you tell me how does it work, etc?

Share this post


Link to post
Share on other sites

When I did my free fall IA, all I did was use a video camera to record me dropping a ball from a height. I dropped it against a wall with a measuring tape attached to it. Just make sure the camera is level, and then you can analyse the video frame by frame on the computer in order to work out it's velocity and time, and thus acceleration due to gravity :)

Share this post


Link to post
Share on other sites

We stuck a measuring tape against a wall. We then setup a video camera on a tripod, and faced it against the wall. We then dropped a ball from some height and recorded it. Then when we looked at the video on the computer, we could see how far it tell in what time, therefore finding its acceleration :)

Share this post


Link to post
Share on other sites

What do you mean by a measuring tape?

Sorry, English isn't my main language..

So you just stop it in the computer?

Wouldn't you play with too little accuracy?

Anyways, tyvm!

Share this post


Link to post
Share on other sites

What do you mean by a measuring tape?

Sorry, English isn't my main language..

So you just stop it in the computer?

Wouldn't you play with too little accuracy?

Anyways, tyvm!

Like, a ruler, but extra long and not hard?

Kinda like below, but a lot bigger writing. From memory, I think that I got a whole heap of peices of paper and stuck them together. Then i ruled lines for like 5cm, 10cm etc in black ink. That way I could just see how much time it took to travel 10cm or whatever...

measuring-tape.jpg

And if you get the video camera 90 degrees to the wall, it should be pretty accurate. And when you analyse it on the computer, use a program that you can skip frames (most camera should have at least 50 frames per second at the very least. So you can get the distances and time pretty spot on :)

Edited by Ezeh

Share this post


Link to post
Share on other sites

Another simple way to measure gravity is to use a mass on a spring or a pendulum. I think that the mass and spring might be a little bit more useful, because the spring constant is usually given with the spring so that is the on I would use. Details on a lot of ways to measure gravity are on the site below:

http://www.earthsci.unimelb.edu.au/ES304/MODULES/GRAV/NOTES/measgrv.html

Share this post


Link to post
Share on other sites

Another simple way to measure gravity is to use a mass on a spring or a pendulum. I think that the mass and spring might be a little bit more useful, because the spring constant is usually given with the spring so that is the on I would use. Details on a lot of ways to measure gravity are on the site below:

http://www.earthsci.unimelb.edu.au/ES304/MODULES/GRAV/NOTES/measgrv.html

I did an experiment to calculate the spring constant for a spring. I don't think they 'come' with the spring. But yeah, SHM is also a great way to measure g.

Share this post


Link to post
Share on other sites

Another simple way to measure gravity is to use a mass on a spring or a pendulum. I think that the mass and spring might be a little bit more useful, because the spring constant is usually given with the spring so that is the on I would use. Details on a lot of ways to measure gravity are on the site below:

http://www.earthsci....ES/measgrv.html

I did an experiment to calculate the spring constant for a spring. I don't think they 'come' with the spring. But yeah, SHM is also a great way to measure g.

I also did an experiment with springs and masses. Very easy way to find g :). Yes, you're right, they don't 'come' with spring constants, but this can always be calculated. I've also done the experiment described in which a measuring tape or scale is placed against a wall and a ball is recorded as it falls. Both nice and simple experiments :) Good luck!

Share this post


Link to post
Share on other sites

ooohhhhh why didn't i read this thread last week? lol.

definitely do a simple pendulum experiment :) it's the easiest way to measure gravity IMO, and this is the first IB physics lab that I did, so it can be said to be easy.

I think there is one more experiment from which I could calculate g too. I forgot though, but I'm not at home now so I'll get back to you on this when I'm home. but pendulum is fairly easy.

Share this post


Link to post
Share on other sites

Yeah i wanted to do pendulums, but my teacher said no pendulums...

How does the spring experiment work btw?

Put a mass on a spring. All springs follow Hooke's law, which states that gif.latex?F=-kx, and thus you can find a relationship using the period of oscillation :)

Edited by Ezeh

Share this post


Link to post
Share on other sites

My class did a very simple experiment to measure g for DC and CE. You take a lab cart and a ramp. Measure the angle of the ramp, and keep increasing the angle and measure the acceleration of the cart (like with a vernier labquest if your school has these). Then we plotted a graph of acceleration vs angle, and got a slope of g.

Good luck with whatever you choose to do!

Share this post


Link to post
Share on other sites

I finally did the experiment, it went alright!

Thnank you guys!

I just dropped objects from great heights, and with that method, it was easier to take data..

Air friction was included in the experiment, it was the subject of the investigations.

Once again, thank you all!

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...