Question

16. Give reasons :
(1) A few dr0ops of oil are poured on the hinges of a door
(2) Compressed and purified air is considered a good lubricant.
(3) We use ball bearings in shafts of motors,
VW Science & Technology​

Answer 1

Answer:

1) Few drops of oil are poured on the hinges of a door, the door moves smoothly by reducing friction. Oil is a lubricant. it helps to reduce friction by being applied over the irregularities of a surface. So, there is no interlocking of irregularities, so, friction reduces, and the door moves smoothly

2) In the machines, the flow of compressed and purified air lowers the friction, hence it acts as a lubricant.

3) Ball bearings are the most common type of bearings and are found in many every day objects, such skateboards, blenders, bicycles, DVD players and photocopiers. This type of bearing is typically used in applications which have a high speed and a low load.