Aeroplanes are given a streamlined shape mainly to reduce which type of friction?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Fluid friction
Air and water are fluids, and the frictional force they exert on a body moving through them is called fluid friction or drag. A streamlined shape, narrow at the front and tapering at the back like the body of a bird or a fish, lets the air flow past smoothly and so reduces this drag.
Why the other options are incorrect
Option (2) Sliding friction — Incorrect. It acts when one solid surface slides over another, such as a box pushed along the floor.
Option (3) Kinetic friction — Incorrect. It is the friction between two solid surfaces moving over each other, the general name that covers sliding friction.
Option (4) Limiting friction — Incorrect. It is the largest static friction between two solid surfaces, reached just before one starts to move over the other.