SOLUTION: The density of platinum is 21.5g/cm^3. If the ring shown in the figure below is crafted out of platinum, how much will it weigh? h = 0.5 cm r = 2 cm 0.15 cm

Algebra ->  Equations -> SOLUTION: The density of platinum is 21.5g/cm^3. If the ring shown in the figure below is crafted out of platinum, how much will it weigh? h = 0.5 cm r = 2 cm 0.15 cm      Log On


   

Question 973255: The density of platinum is 21.5g/cm^3. If the ring shown in the figure below is crafted out of platinum, how much will it weigh?
h = 0.5 cm
r = 2 cm
0.15 cm
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
.
Assuming 0.15cm is the thickness, the volume will be
volume of the disk with outside radius (r) and thickness (h)
minus the the inner (empty) disk with radius (r-0.15cm) and
thickness h:
%28pi%29r%5E2h-%28pi%29%28r-0.15cm%29%5E2h=volume of metal in ring
%28pi%29%282cm%29%5E2%280.5cm%29-%28pi%29%282cm-0.15cm%29%5E2%280.5cm%29=volume
%28pi%29%282cm%5E3%29-%28pi%29%281.71cm%5E3%29=volume
%28pi%29%282cm%5E3-1.71cm%5E3%29=volume
%28pi%29%280.29cm%5E3%29=volume
0.911cm%5E3=volume
.
Mass=density x volume:
mass=%2821.5g%2Fcm%5E3%29%280.911cm%5E3%29
mass=19.587g