Saved Bookmarks
| 1. |
The diameter and thickness of a hollow metals sphere are 12 cm and 0.01 nrespectively. The density of the metal is 8.88 gm per cm. Find the outer surfacarea and mass of the sphere.6. |
|
Answer» Diameter of sphere from outside = 12 cm Radius from outside R = 6 cm Surface area = 4 πR² = 4 (22/7) (6²) = 452.57 cm² Now, Thickness of sphere = 0.01 m = 1 cm Diameter from inside = 12 - 2 = 10 cm [ -2 is done to reduce from both sides ] Radius from inside r = 5 cm Volume of this sphere V = Volume of outside sphere - Volume of inside sphere So, V = 4/3 πR³ - 4/3 πr³ = 4/3 π (R³ - r³) V = 4/3 (22/7) (6³ - 5³) V = 4/3 (22/7) (91) V = 381.33 cm³ Now, Density = Mass / Volume Mass = Density x Volume Mass = (8.88) x (381.33) Mass = 3386.24 g = 3.38624 kg |
|