Physics

[richarddean]

Hi Guys can anyone help as I seem to have conflicting answers for this

An Object weighs 237kg and displaces 123 litres of water. How much additional seawater do you need to displace to give the object 40 kg positive buoyance

I came up with the answer of 146 litres, but a freind says it is 68.3 litres

Who is right

My math was 237 + 40 = 277

277/1.03=268.93ltrs
268.93-123lt =145.93

 

[Ifoundnemo]

more another question than an answer in the second line your working you subtract 123lt where did you get that figure from?

 

[SparticleBrane]

I'd be more willing to answer if you actively participated in discussion instead of relying on ScubaBoard to answer your homework. 90% of your posts are dealing with DM and physics questions.

 

[SkullDeformity]

I'd be more willing to answer if you actively participated in discussion instead of relying on ScubaBoard to answer your homework. 90% of your posts are dealing with DM and physics questions.

Wow, you're right.

 

[richarddean]

Sparticlebrane I am not asking you to do the sums for me, I have already done the sums. Just want to know if perhaps I messed up or my friend messed up

 

[SparticleBrane]

In your race for correct answers, you missed the underlying concepts. This is a concepts question to see if you understand the ideas, not to see if you can do math.

 

[richarddean]

So then the question is have I the concept right or wrong, if its wrong then surely I need telling so I dont keep making same mistake

 

[SparticleBrane]

You have the correct answer... Not sure where your friend came up with his answer.
I had to do it in imperial units to check though. :11:

 

[richarddean]

thank you, thats all I need to know, the reason I asked this was because my friend for whatever reason thought you had to minus the 40kgs, and I was trying to explaine to him that we was displacing more water so it had to be +
thank you for your assistance

 

[Steve R]

Can I at least make the assumption you paid a 'pro' to teach you this DM course?

Padi by any chance?

If so, I suggest you get your monies worth and ask him to actually teach this stuff.

I just read most of your posts. Did the guy teaching you actually know how to do it himself, or is it an inability to get it across to you in a way that it is understood that is the problem?