Increasing and decreasing friction ….
Answers
Explanation:
traffic signal board, indicating 'SCHOOLAHEAD', is an equilateral triangle with side 'a'.
Find the area of the signal board, using Heron's Formula. If its perimeter is 180
Friction is one force which exists irrespective of the fact that an object is at rest on in motion. At times we need to increase or reduce its value in relation to the demands of the situation. For example, if we are playing carrom, it is important that the amount of friction on the board should reduce. In contrast to this, if we are lifting an object, the friction between our hand and the object should be sufficient to prevent the object from slipping down from our hand.
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Let us now study the different ways used to increase and reduce friction.
Increasing Friction :-
- Increase the number of groves and ridges in an object so that when it is placed on another surface, the interlocking between them gets firmly intact. For example, soles of sports shoes have many groves to increase friction between the shoes and the ground. Tyres of vehicles also have groves or treads to get bonded firmly to the roads.
- Straps of briefcases and bags have a comparatively rough surface to avoid slipping from our hands.
- Weightlifters and gymnasts apply a chalk on their hands which increases friction and helps them to have a firm grip on the weights.
Reducing Friction :-
- Friction in the game of carrom board is reduced by putting powder on the board, which makes the striker move swiftly on the board.
- Oiling aur applying grease on parts of machinery reduces friction and makes them work smoothly without any wear and tear. This helps in increasing the efficiency and less heat is lost. Liquids that reduce friction are known as lubricants.
- Use of ball bearings instead of non-moving metal-to-metal contact in fans and machinery further reduces friction as sliding friction is transformed into rolling friction.