The Weight Of My Balls

[RATTER15]

I have had an enquiry to make a concrete ball weighing 100kg. What diameter would this concrete ball need to be please. Its a side line of mine :-)

[murraymints]

OOO you are awful....

[RATTER15]

Minty, you just have a mucky mind!! I'm sure you have seen my balls many times!!

[murraymints]

EEK ! that was supposed to be secret !!

[Tilly2]

Nice to see you back, Ratter. Hope you are both well.

[RATTER15]

Thanks Tilly, both well here thanks.

[Tilly2]

Good to hear. I do hope someone can help with your question.

[mallyh]

read your headline and spilt coffee down my front lol xx

[RATTER15]

Lol Mallyh, it was supposed to get attention but don't waste your coffee.

[aelmpvw]

//The Weight Of My Balls//
i suppose you could wedge some kitchen scales in your groin area ...

[Fitzer]

A sphere with a radius of 215mm should weigh 100kg if made of standard concrete

[murraymints]

Fitzer..you are clever..can you explain how ?

[Flonska]

If I have got this right . . .

100kg = 220 lb approx

Using medium concrete a 220lb sphere would have a diameter of approx 17.6 inches.

Hope this helps?

[Chipchopper]

Its a pity the person didn't specify the diameter of the ball rather than the weight, I think that would have been easier.

[jackthehat]

Somwhere in the region of 430mm diameter but it depends upon the mix.

[RATTER15]

Thanks Fitzer, So can I just double the size of the ball to double the weight? I would imagine so.

[Fitzer]

Google was my friend, I simply looked up the weight of concrete which told me that 1kg was 0.00042 cubic meters, so 100kg would be 0.042 cubic meters, another website then let me input that as the volume of a sphere and voila. I did use to know the formula for volume of a sphere but had forgotten, can't reproduce it here as it requires superscript and fractions :-)

[bhg481]

RATTER - NO. The weight increases as the cube of the radius, so doubling the radius multiplies the weight by 8.

[jackthehat]

V= 4/3 π rxrxr
a cubic meter of concrete weighs 2400kg

[Fitzer]

Well no, if you double the radius of a sphere you multiply the volume by about 8. Just Google volume of a sphere and it brings up a calculator

[spathiphyllum]

This will take some precise maths