Q69 of 100 Page 231

What is drag? Give two examples of a drag force.

The drag is the other name for fluid friction. It resists the motion of any object that travels in fluid.

Examples: 1. A boat travelling in water.

2. An aeroplane moving in the sky.

What is the difference between static friction and sliding friction? For' a given pair of objects, which of the two is greater?

How can a very heavy machine be moved conveniently from one place to another in a factory? (No crane is available for this purpose).

How can you reduce the drag on something moving through the air?

What is meant by 'streamlined shape'? Name an object which usually has a streamlined shape.