InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
A bullet is in the shape of a cone mounted on a cylinder. The radius of the cylinder is 0.7 cm and it is 4 cm long. If the volume of the bullet is 7.7 cm3, find the height of the conical part?1. 2 cm2. 3 cm3. 5 cm4. 8 cm |
|
Answer» Correct Answer - Option 2 : 3 cm Given: Radius of cylindrical part = 0.7 cm Height of cylindrical part = 4 cm Volume of Bullet = 7.7 cm3 Concept: The radius of the conical part will be same as the radius of the cylindrical part because it is mounted on it. The mass of the bullet will be the sum of the mass of the cylindrical and conical part. Formula used: Volume of cone = (1/3)πr2h Volume of cylinder = πr2h Calculation: Let, the height of the conical part = ‘a’ cm ∵ Volume of Cylindrical part = πr2h = (22/7) × 0.7 × 0.7 × 4 = 6.16 cm3 Volume of conical part = (1/3)πr2h = (1/3) × (22/7) × 0.7 × 0.7 × a = (10.78 × a)/21 cm3 ∵ Volume of bullet = Volume of Cylindrical part + Volume of conical part ⇒ 7.7 = 6.16 + (10.78 × a)/21 ⇒ 7.7 × 21 = (6.16 × 21) + (10.78 × a) ⇒ 161.7 = 129.36 + 10.78a ⇒ 161.7 – 129.36 = 10.78a ⇒ 32.34 = 10.78a ⇒ a = 32.34/10.78 ⇒ a = 3 cm |
|