Question
Physics Question on mechanical properties of fluid
When a body falls in air, the resistance of air depends to a great extent on the shape of the body. 3 different shapes are given. Identify the combination of air resistances which truly represents the physical situation. (The cross sectional areas are the same) 
1. Disc 2. Ball 3. cigar sheped
A
1 < 2 < 3
B
2 < 3 < 1
C
3 < 2 < 1
D
3 < 1 < 2
Answer
3 < 2 < 1
Explanation
Solution
Fig. 3 is stream lined, so air resistance for it will be minimum. For fig. 1 surface area is maximum, so air resistance for it is maximum. Hence, correct sequence is 3<2<1.