Determining 'g' Using a Free-Fall Method - PRACTICAL

Determining 'g' Using a Free-Fall Method - PRACTICAL - A Level Physics

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7 жыл бұрын

In this video I go through an AQA Physics A Level Required Practical that uses a free-fall method experiment to calculate the acceleration due to gravity, g. (This is AQA Required Practical 3.) This is also the OCR A Level Physics PAG 1.1 Practical.
Dropping a steel ball bearing through light gates can be used to find the acceleration due to gravity. Recording the time taken for it to fall as you then change the distance between the gates allows a graph to be plotted and the value of 'g' to be determined.
See instructions for all the practicals at www.alevelphysicsonline.com/ye...
Thanks for watching,
Lewis
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Пікірлер: 90

@user-mm9kv9nn5w 3 жыл бұрын

Me: Gotta do the experiment to get to the accurate value of g. Systematic and Random Errors: Nope

@minonarambewela7573 Жыл бұрын

You can avoid the systematic error by using a better electromagnet which does not retain magnetism when turned off and random errors by keeping your eye level perpendicular to point of reading, along with using a metre ruler with low uncertainty.

@djstores_dylan 5 жыл бұрын

This is a lifesaver! Thank you!

@TensaiV Жыл бұрын

im so fucked

@auuughhhbygarrison3920 2 ай бұрын

with u man🤣🤣🤣🤣🤣

@subscriberswithoutanyvid-ro4nr 5 жыл бұрын

Can you upload all the core practicals and excess ones for the new specifications please?

@nadiaditta4647 5 жыл бұрын

thank you so much for this

@kujojotaro5599 2 жыл бұрын

Amazing video

@letslearnwithrahatfatima7336 6 жыл бұрын

i didnot understand the part where u wrote 2u, please clarify.

@milesblack1830 Жыл бұрын

How do you know u tho, as the cube will have accelerated before passing through the first light gate?

@ebukaz 6 ай бұрын

What is g for no initial velocity for a object that just falls and for a object that's thrown up into the air with an initial velocity upwards in free fall?

@stephengevanni8315 7 жыл бұрын

Thanks for this video; much appreciated sir. I have a question: you mentioned using a cube is better than a sphere, why is that?

@sarujanrupan4831 3 жыл бұрын

I think it's more more likely to stay on the electromagnet.

@rand2863 Жыл бұрын

Why should x be constant in this experiment?

@kienang9679 7 жыл бұрын

I suppose the function of each light gate is to measure the velocity, the first one is used for measuring the initial and the second one is for final velocity, then we use v^2=u^2 + 2aS to find the acceleration.

@alejandrobenavides5035 7 жыл бұрын

I think hes using the light gate as a stopwatch to then plot a graph with x axis as time

@alejandrobenavides5035 7 жыл бұрын

So basically the graph will work out the acceleration for you because youre seeing the change in velocity (S/T) -y axis by the time (T) - x axis

@yaasinalikondeth6724 Жыл бұрын

No he mentioned that the distance 'x' was to reach the terminal velocity, so meaning there wont be a change in speed anymore. So using v2 = u2 + 2as wouldnt be useful. The point of the light gate is to act as a timer between the point at which it reached TermV and the point it reaches the Bottom

@minonarambewela7573 Жыл бұрын

Sorry bud, but this does not work as V is a variable whose value we cannot calculate instanteously. Rather, we must use S = ut + 1/2at^2 assuming that u is 0 and that you know the displacement S.

@nefarious8278 3 жыл бұрын

How accurate is this experiment

@ravi31 7 жыл бұрын

Can you upload videos of all the practicals required for AS Physics pls!!

@PhysicsOnline 7 жыл бұрын

Ah V I have! In the video description there is a link to all the required practicals for AS.

@ravi31 7 жыл бұрын

i'm going through a unit 1 physics paper and there's a question on practicals! for unit 1, will they only ask questions on the core practicals listed on your site?

@ravi31 7 жыл бұрын

this is for the IAL spec btw, I thought practical questions are supposed to be on unit 3 but they're appearing on unit 1?

@PhysicsOnline 7 жыл бұрын

You have to know the core practicals - these are slightly different for each exam board so make sure you read the specification thoroughly. But they could throw in a few other practicals - but these will be about something you will have learnt about and will be about your ability to answer practical questions or interpret data.

@fahrenheit2101 3 жыл бұрын

Is this similar to how we got the value of 9.806... for g on Earth? Or did that come about in a completely different way?

@adbj 4 ай бұрын

Quiet smelly poo

@the_hasnat 4 жыл бұрын

why would it be better to use a cube??

@Mking99999 5 жыл бұрын

never thought id need this video for university too

@PhysicsOnline 5 жыл бұрын

Mayur Which degree is that?

@abdirahman4642 5 жыл бұрын

GCSE and A Level Physics Online can you please send me the table of your results to compare against mine also your graph which is fully plotted. This would be very much appreciated

@cateyestudios6592 2 ай бұрын

@@abdirahman4642 lmao nice try

@thecodinglad6830 5 жыл бұрын

Could we use the equation v = u + at to plot the graph?

@zohaibgulawan9070 2 жыл бұрын

You dropping from distance you can do I think but you have to measure time them

@zohaibgulawan9070 2 жыл бұрын

And ik I'm late

@rayhanulchowdhury3560 3 жыл бұрын

What one advantage and disadvantage of making the distance between the light gate as large as possible?

@raheebmohammed9144 3 ай бұрын

I..... think it'll reduce percentage uncertainty

@rayhanulchowdhury3560 3 ай бұрын

😂thanks for the reply even tho my exams were 2 years ago😂😂

@r.umarskhan 5 жыл бұрын

Does it matter at what velocity the object emters the first light gate?

@benpilkington2873 5 жыл бұрын

it s easiest if it is zero because then in the equation you can have u (initial velocity) as 0

@AK476056 5 жыл бұрын

No my friend. As long as you have got a value for the initial velocity and the final velocity, you are able to work out the acceleration using the time and the distance between the light gates.

@tanishabanerjee8331 3 жыл бұрын

I have a question about the significance of u, if the ball is being dropped, won't it have 0 initial velocity, or do we take the initial speed of when it passes the first light gate?

@markm4952 3 жыл бұрын

Since the initial time doesn't start until it passes through the first gate, that is our initial reference point sonthatbis what we consider to be u. V=0 at some negative time before u

@xxxx-lt8br Жыл бұрын

@@markm4952 so how would we find u?

@umamahrehman2780 6 жыл бұрын

Thank you for the helpful video. Just one thing: why do we need to rearrange the formula? (stupid question I know, but I just need to clear it up)

@PhysicsOnline 6 жыл бұрын

Umamah Rehman This is just one way of doing it, so that the gradient is exactly equal to the acceleration due to gravity.

@umamahrehman2780 6 жыл бұрын

OK that makes sense. Do we need to know why the formula is arranged in this particular way? Also, we don't need to find u for this version of the experiment, do we? As long as distance x is constant, u shouldn't affect the results?

@PhysicsOnline 6 жыл бұрын

Umamah Rehman That’s correct. You don’t have to remember why the formula is like that, but it is something you should be able to follow.

@umamahrehman2780 6 жыл бұрын

Thank you very much for helping out!

@umuthalil5001 7 жыл бұрын

is there any sources of error that might occur during this experiment

@taco1362 5 жыл бұрын

make sure the stand cannot topple over by clamping it securely

@taco1362 5 жыл бұрын

also make sure you are measuring distance between the two lightgates from eye level .

@crazyhq270 4 жыл бұрын

You can hear all the flat earthers scream in pain.

@bebetiff8500 5 жыл бұрын

Why did you add the 2s in the equation ?

@benpilkington2873 5 жыл бұрын

he multiplied everything by 2

@cosminlive199 7 жыл бұрын

When we did the required practical we used s (dist.), as the independent variable, and t^2 as the dependant, giving a gradient of 2/g. Which method of taking data is better?

@woopwoop2601 7 жыл бұрын

Cosmin Covrig depends exactly what version of the experiment you do. Many of them don't require the initial speed part of the equation since you don't have initial speed to take into account, in which case t^2 against h is fine, the graph should pass through the origin and the gradient is equal to 2/g. As I say, it really does depend which version you're doing as to what data you need to take into account.

@jiaqima1043 3 жыл бұрын

there's a mistake in the video, notice that in the equation '2S/t=2u+at' t cannot equal 0, so in the graph, u should plot it out.

@minonarambewela7573 Жыл бұрын

No 2s/t cannot reach 0, hence why the graph does not start from the origin.

@menoxes1626 4 жыл бұрын

how do measure the initial velocity?

@amirpenkar947 4 жыл бұрын

It's 0 because it starts at rest

@wrexet8246 Жыл бұрын

@@amirpenkar947 no because then 2u=0 which isnt the case for this mans graph

@kaibain3277 3 жыл бұрын

why is a cube better than a ball?

@S.I.A.R908 7 ай бұрын

Are you working with uplearn sir?

@PhysicsOnline 7 ай бұрын

They licensed some of my videos for their physics content!

@abdurrasheedsadiq7549 7 жыл бұрын

I got g = 14.6 when I did this xD

@samknight4313 3 жыл бұрын

Seems good enough

@louisdunn8539 Жыл бұрын

I did better with a rock and 3 rulers. Bitch

@trrahman2900 6 жыл бұрын

Can anyone tell me how do we get the value of 'u'?

@benpilkington2873 5 жыл бұрын

it is the initial velocity, so it is easiest if you drop the ball just above the light gate so it is zero

@aryandhaka4981 5 жыл бұрын

in this wouldn't the value of initial velocity(u) be 0? leading to the equation to be s = 0.5 x a x t^2 ?

@AK476056 5 жыл бұрын

ARYAN DHAKA No, because the initial velocity 'u' is taken to be the velocity of the object at the instant it passes through the top light gate, not the instant the object is dropped (in which case, 'u' would indeed be zero as it would be dropped from rest).

@HarveyDoe 7 жыл бұрын

You can't plot a graph from this unless you change 's' so how is 'x' constant?

@AK476056 5 жыл бұрын

You lower the bottom light gate. The top light gate, closest to the electromagnet, must be at a fixed distance from the drop height the entire time. So 'x' is kept constant.

@tawraveins854 4 жыл бұрын

Is calculating "u" important? Or I'll plot the graph and then find the y-intercept with a best fit line?

@nasirmuhammad8768 4 жыл бұрын

"U" will be zero as the object starts from rest, so no

@Arch_-ss2xu 9 ай бұрын

I don’t get y u put a 2 infront of ut +at^2 ?

@zodiAAAHHH 6 ай бұрын

he multiplied everything by 2 to get 2s because the graph plots 2s/t

@VK-il9kv 3 жыл бұрын

um why is it better to use a cube than a sphere?

@temourahmed5979 3 жыл бұрын

So it dosent roll off or bounce when it hits the floor

@NafSlaveOfAllaah 5 сағат бұрын

Bismillah and Alhamdulillah As Salaam alaikum brothers and sisters ❤!

@spr1ng21 Жыл бұрын

why does u double? 2:28

@j8los 2 ай бұрын

he got rid of the 1/2 so he needed to times everything by 2

@temomcphillip8988 2 жыл бұрын

what happened to the squared of T?????? or am I the only one confused??

@MH-wh9ek 2 жыл бұрын

he divided the whole equation by t

@bebetiff8500 5 жыл бұрын

Actually, why didn’t you rearrange the equation to make acceleration the subject of the formula ?

@nadiaditta4647 5 жыл бұрын

Because you're plotting 2s/t (on the y axis) against t (on the x axis) so you make 2s/t the subject

@jameskonefal3453 2 жыл бұрын

I think it is because we want the acceleration to be the GRADIENT of the graph. That would not be the case if acceleration was on one of the axes. It just so happens that when you plot a graph of 2s/t (which is in itself a totally abstract concept) against the time, then the gradient equals the acceleration, which is precisely what we are trying to find in this experiment to determine the value of g. I hope I'm right?