2. Rachel, an engineering student, was asked to make a model shaped like a cylinder with two cones attached at its two ends by using a thin aluminium sheet. The diameter of the model is 3 cm and its length is 12 cm. If each cone has a height of 2 cm, find the volume of air contained in the model that Rachel made. (Assume the outer and inner dimensions of the model to be nearly the same.)

Answers (1)

The volume of air present  =   Volume of cylinder   +   2 (Volume of a cone)

Now, the volume of a cylinder :    =\ \pi r^2h

or                                         =\ \pi \left ( \frac{3}{2} \right )^2\times 8

or                                         =\ 18\pi \ cm^3

And the volume of a cone is :

                                             =\ \frac{1}{3} \pi r^2h

or                                          =\ \frac{1}{3} \pi \times \left ( \frac{3}{2} \right )^2\times 2

or                                          =\ \frac{3}{2} \pi \ cm^3

Thus the volume of air is :

                                        =\ 18 \pi\ +\ 2\times \frac{3}{2} \pi \ =\ 21\pi

or                                      =\ 66\ cm^3

                                           

Preparation Products

JEE Main Rank Booster 2021

This course will help student to be better prepared and study in the right direction for JEE Main..

₹ 13999/- ₹ 9999/-
Buy Now
Rank Booster NEET 2021

This course will help student to be better prepared and study in the right direction for NEET..

₹ 13999/- ₹ 9999/-
Buy Now
Knockout JEE Main April 2021 (Subscription)

An exhaustive E-learning program for the complete preparation of JEE Main..

₹ 4999/-
Buy Now
Knockout NEET May 2021

An exhaustive E-learning program for the complete preparation of NEET..

₹ 22999/- ₹ 14999/-
Buy Now
Knockout NEET May 2022

An exhaustive E-learning program for the complete preparation of NEET..

₹ 34999/- ₹ 24999/-
Buy Now
Exams
Articles
Questions