# Mass Question--need help! [closed]

A probe sent to the surface of Mars uncovers a pure platinum disc inscribed with the message, "We'll be right back" (in Martian, of course!). The disc is 4 inches thick and 0.9 meters in diameter. The density of platinum is 21,450 kg/m3. What is the mass of the platinum disc in pounds (lbm)? The Martian acceleration due to gravity is 3.61 m/s2 while Earth's gravitational constant is 32.2 ft/s2. What is the Earth weight of the disc in Newtons?

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## closed as off topic by sdcvvc, Asaf Karagila, Alexander Gruber♦, 5PM, PaulFeb 9 '13 at 2:55

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What have you tried? –  anorton Feb 9 '13 at 0:42
Is it mass question or math question? –  Asaf Karagila Feb 9 '13 at 0:42
I guess this is homework? (looking at your other question) Don't really know where to start "no idea" is not very precise. What do you know, what is your problem? Just getting the answer on here will not help you. –  example Feb 9 '13 at 0:44
SHOUTING is considered rude. And simply pasting a question without adding your own thoughts isn't the best way towards an answer either. –  MvG Feb 9 '13 at 0:47

$$\mbox{density} = \frac{\mbox{mass}}{\mbox{volume}}$$ so to find the mass, find the density and volume and solve appropriately.
$$\mbox{force} = \mbox{mass}\times\mbox{acceleration}.$$ Weight is force exerted by gravity. To find weight, find mass and acceleration due to gravity and solve appropriately.