How to calculate direct proportion

How to work with direct proportion is aimed at around grade A / B at GCSE. The video deals with calculating 'k' - 'the constant of proportionality.'

There is an example of an A grade question:
"Winnie drops a stone down a well. The spped of the stone, v m/s, is directly proportional to the time, t seconds, since she dropped it.
After 0.5 seconds the stone is travelling at 4.9 m/s.
a) Find a formula for v in terms of t
b) Calculate the speed of the stone after 1.2 seconds"

I hope the video helps and please do leave a comment - thanks!

[kakadawdy]

When your mind breaks due to mymaths homework

[sauce]

As someone who hasnt seen this material in close to 6 years and now needs it for their trade teachers like you who put their work online are fantastic. Cheers from america.

[Em-qrfs]

I just realised my teacher has set this on our end of year 8 exam I'm 12 I don't know why I need this

[silkestrachan]

Really helped me understand direct proportion! Thank you, is there a video on inverse proportion or not?

[MrLukeyMorrison]

very useful, now i might not fail my maths exam

[aryanisverycool]

im looking at this during an online exam

[Kattie]

Great explanation, but can you improve your hand writing because I sometimes don't understand what you are writing. But anyways thanks for your help it really helped me.

[stephenbarker]

can you help with this question y is directly proportional to x find a formulae for y in terms of x part 2 x = 500 y = 10 find the value of y when x is 350

[asfaranant]

Y varies directly as X. If y=6 when X=2 find. a) y when x =5.5 b) x when y =12

[selinanessa]

I have that worked out example question in my revision book, your explanation helped so thanks. By the way the answer was 11.76 m/s not 11.96 m/s

[KevinShroff]

Thank you very much for the video. I couldn't understand this in two lessons of math, but I understood easily from your 7 minute video. Thank you again.

[bushratahir]

Many thanks, but I wanted to ask that how is the velocity directly proportional to the time?

[IamCordelia-qndj]

Can you imagine how many folds are in the brain of a mathematician?🤯😵‍💫

[mehroonisaahmed]

i am stuck on a question ..plz can u help

1) x is directly proportional to y.
when x=3, y=b
work out the value of y when x=8

[VRG]

Very clear and easy to understand!THANKS A LOT!!!

[laurawiles]

Thank you! How do you express things in terms of other things. On my homework, I have a question about direct proportion but, I'm not sure how to do it.
"W and P are both positive quantities,
W is directly proportional to the square root of P.
When W=12, P=16.
Express W in terms of P."
I've found the constant, which is 3 (I think) but, I am unaware of how to do the rest. I'm not sure how you'll respond to this but, I will really appreciate help. Thank you again 😃😃😃

[dhruv]

hello Simon do you do tutoring for maths if you do could you please reply
Thanks

[amybakrania]

this is great thank you! but how would you do this one?

The cost (£C)of building a circular pond is proportional to the square of its diameter, d meters. A pond with a diameter 2 meters costs £52. find the formula for C in terms of d.

thank you!

[foxgames]

It's e is directly proportionate to h or e=kh

[iiDilzzzy]

I the only thing I was confused by was when you said k x 0.5 on ur calculator how would you write k on your calc?