SOLUTION: the diameter of an iron ball used in putting the short is 12cm. the density of iron is 7.8g/cm^3. calculate the mass of the ball in kg to 3 significant figure.

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Question 1126290: the diameter of an iron ball used in putting the short is 12cm. the density of iron is 7.8g/cm^3. calculate the mass of the ball in kg to 3 significant figure.
Found 3 solutions by addingup, MathLover1, josmiceli:
Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
Calculate the volume:
V = 4/3 x Pi x r^3 = 7238.23
Calculate the mass:
mass = volume x density
7238.23*7.8 = 56,458.194

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

given:
d=12cm+->r=6cm
Density=+7.8%28g%2Fcm%5E3%29

V+=+%284%2F3%29pi%2Ar%5E3+
V+=+%284%2F3%29pi%2A%286cm%29%5E3+
V+=+%284%2Fcross%283%29%29pi%2Across%286%292cm%2A%286cm%29%5E2
V+=+4pi%2A2%2A36cm%5E3
V+=+4pi%2A2%2A36cm%5E3
V=+288pi%2Acm%5E3

Mass+=+Density+%2A+Volume
mass+=%28288pi%2Acm%5E3%29%2A7.8%28g%2Fcm%5E3%29
mass+=%28288pi%29%2A7.8g
mass+=7057.27g
in kg: 1g+=+0.001kg

mass+=%287057.27%2A0.001+%29kg
mass+=+7.05727kg
mass+=+7.057kg


Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
For a sphere:
+V+=+%284%2F3%29%2Api%2Ar%5E3+
+d+=+12+ cm
+r+=+6+ cm
------------------------
In terms of units:
[ g/cm3 ]x[ cm3 ]x[ kg/g ] = [ kg ]
+V+=+%284%2F3%29%2Api%2A6%5E3+
+V+=+904.7787+ cm3
+7.8%2A904.7787%2A%28+1%2F1000+%29+=+7.057+
7.057 kg