The Student Room Group
I'll help you if someone hasn't contacted you by now.
Reply 2
No one has yet, you're the first.

Would it be better to speak in email or should i post the question here?

Thanks,

Liam
Post it here, cos then if i can't help maybe someone else can.
Reply 4
Ok, It's a bit hard as there is a diagram supplied which obviously I cannot supply here.
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'A clay bowl is in the shape of a hollow hemisphere'

The external radius of the bowl is 8.2cm
The internal radius of the bowl is 7.7cm

Both measurments are correct to the nearest 0.1cm.

The upper bound for the volume of clay is kpie3 (kpiecubed)

Find the exact volume of k.
well you want the external radius of the bowl to be as large as possibly so that would be 8.25 and you want the internal radius to be as small as possible so that's 7.65. So you calculate the external volume and subtract the internal volume.
Thats a funny question. Why is it kpi³? Do you have the answer?
Reply 6
Thanks,

oops....sorry i meant to write kpi cm3

So assuming k is 8.25 - 7.65 = 0.6

0.6pi = 1.88495592

Doesn't seem right to me somehow

Kpi = upper bound for the volume of clay
No, you can't do that. You have to use the two radii to calculate the two volumes.
V=4pi r³/3
so [4 x 3.14 x (8.25)³/3] - [4 x 3.14 x (7.65)³/3]

which gives 477cm³ or 152pi cm³
Reply 8
Thanks that is great. Fantastic.

Also, just one more :smile:

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A cylinder has a diameter of 12cm and a height of 18cm

Calculate total surface area of cylinder.

Give answers correct to 3.s.f
Reply 9
the1liamg
Thanks that is great. Fantastic.

Also, just one more :smile:

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A cylinder has a diameter of 12cm and a height of 18cm

Calculate total surface area of cylinder.

Give answers correct to 3.s.f


A cylinder is basically made up of a rectangle and 2 circles. The rectangle has one side the same length as the circumference of the circle and the other side is the height of the cylinder. You multiply these 2 sides together to get the area of the rectangle and to find the area of the circle use (pi)r^2 and multiply this area by 2 as there are 2 circles (one at each end of the cone.

I hope this makes sense - if not post another reply and i will do the claculation for you!!! :biggrin:
Reply 10
So it is....

(pi 6squared) x 2 x 18

Or 12 x 18 + 2x (pi6squared)
Reply 11
the1liamg
Hello,

I have my maths exam on Monday (edexcel calc) and there is no way of me seeing my teacher before then.

Is anyone prepared to help me and go through a couple of questions with me?

Just a couple of past paper questions I am having trouble with or need checking.

I need to make up marks, well you all now why by now!!

If you can help me (and i hope you can!) contact me by:

Msn: [email protected]

AOL: [email protected] (Email or AIM)

Thanks a lot,

Liam



You have the exam on Monday. Don't you mean Tuesday?
Reply 12
Yes, yes I do.