(a) rollers are used for transporting luggage.
(b) metal chains are wrapped on tyres when they run on icy roads.
(c) aeroplanes and car bodies, are made more pointed along their fronts.
(d) talcum powder is put on a carrom-board before a game.
(a)Because rolling friction is smaller then sliding friction,therefore it is easier to transport a bag fitted with rollers.
(b)to increase friction by incresing irregularities so that they donot slip on ice.
(c)This process is known as streamlining,giving a special shape to objects that have to overcome fluid friction,therfore aeroplanes and cars are given this shape so that they can reduce friction.
(d)to reduce friction so that the coins can slide easily over the board,here talcum powder is used as lubricant
HERE'S YOUR ANSWER BRO
a) Rolling friction is less than sliding friction. So, it is easier to transport luggage through rollers.
b) Icy roads are slippery and have less friction. So, metal chains are wrapped on tyres to create high friction so that, cars or trucks can easily move on these roads.
c) Aeroplanes and car bodies have streamlined shape bodies to reduce drag. The streamlined shape body experiences minimum resistence when travelling though water or air. It helps to reduce friction.
d) We sprinkle powder on carrom board to make the surface board smooth. It reduces the friction between the surfaces of the carrom board. So, that the striker of the carrom board can move easily on carrom board