Tag: friction: a necessary evil

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Multiple choice physics friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it friction: a necessary evil

Why do we sprinkle powder before playing caroms?

  1. To increase friction

  2. To decrease friction

  3. To increase or decrease the friction depending on the type of the game played.

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Powder acts as a lubricant to the surface and reduces friction so that the game can be carried on smooth surface.

Multiple choice physics friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it friction: a necessary evil

To keep machines running smoothly and to avoid wear and tear of machines, the best and the most commonly used lubricant is:

  1. Powder

  2. Sand

  3. Oil

  4. Water
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Oil is the best and the most commonly used lubricant used for keeping machines running smoothly and to avoiding wear and tear of machines as it reduces the friction more effectively.

Multiple choice physics friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it friction: a necessary evil

The force which prevents us from slipping while walking on the road is:

  1. muscular force of our body

  2. gravitational pull by earth

  3. frictional force

  4. balanced forces of nature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When we push the ground with our feet, the friction provides a forward reaction to our push and sends us forward. Walking on smooth ground is difficult because the frictional force is not great enough to prevent slipping.


Option C is correct.

Multiple choice physics friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it friction: a necessary evil

In which of the following cases more friction is desirable?

  1. Movement of piston in a cylinder

  2. Braking of a vehicle

  3. Running on a track

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.

Brakes is a type of automotive brake that slows or stops a vehicle by converting kinetic energy into heat energy, via friction. The heat energy is then dissipated into the atmosphere. 
Hence, braking of a vehicle happens due to friction.

Multiple choice physics friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it friction: a necessary evil

The surface of the head of a matchstick and sides of a match box are deliberately made rough to

  1. Increase friction

  2. Decrease friction

  3. Increase pressure

  4. Decrease amount of heat
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Answer is A.

A match is a small stick of wood or strip of cardboard with a solidified mixture of flammable chemicals deposited on one end. When that end is struck on a rough surface, the friction generates enough heat to ignite the chemicals and produce a small flame. Some matches, called strike-anywhere matches, may be ignited by striking them on any rough surface.
Hence, the surface of the head of a matchstick and sides of a match box are deliberately made rough to increase friction.