Tag: friction

Questions Related to friction

Which of the following are done to increase friction?

physics friction increasing and reducing friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it

  1. Greasing the machines

  2. Treading the tyres

  3. Sprinkling powder on the carom board

  4. All of the above

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Correct Option: B
Explanation:

The tyres are treaded to make it rough so that the frictional force increases when it comes in contact with the road. 

All others are done to decrease friction.

The steps for decreasing friction includes:

physics friction increasing and reducing friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it

  1. ball bearing used in moving parts of a machine

  2. the streamlined shape of an aircraft

  3. the layer of air between the hull of a hovecraft

  4. none of these

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Correct Option: A,B,C
Explanation:

1) As rolling friction is less than sliding friction the shafts are fixed on ball bearing so that so that friction is reduced considerably.

2) The friction due to air is reduced by making the automobiles streamlined. Streamline shape allows more air and water to flow easily which offers least resistance.
3) Another way of reducing friction is to separate surfaces by air. This principle is used in hovecraft. The layer of air reduces friction allowing aircraft to move easily.

If we apply oil on door hinges, the friction will:

physics friction increasing and reducing friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it

  1. increase

  2. decrease

  3. disappear altogether

  4. will remain unchanged

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Correct Option: B
Explanation:

Lubrication always decreases friction between two surfaces. Hence putting oil will decrease friction.

In a large commercial complex there are four ways to reach the main road. One of the path has loose soil, the second is laid with polished marble, the third is laid with bricks and the fourth has gravel surface. It is raining heavily and Paheli wishes to reach the main road. The path on which she is least likely to slip is:

physics friction increasing and reducing friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it

  1. loose soil

  2. polished marble

  3. bricks

  4. gravel surface

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Correct Option: A
Explanation:

Loose soil will provide the maximum friction and hence less chances of slipping.

Which of the following is used to reduce friction :
1. Streamlines
2. Use of ball bearings
3. Lubrication

physics friction increasing and reducing friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it

  1. 1 & 2 only

  2. 1 & 3 only

  3. 2 & 3 only

  4. 1, 2 & 3

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Correct Option: D
Explanation:

All the mentioned option are correct.

Streamlines reduces the friction in fluid.
Use of ball bearing reduces the friction in machines rotating parts.
Lubricants are used in machines  and moving parts to reduce friction.

Option D is correct.

Why are efforts made to reduce friction?

physics friction increasing and reducing friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it

  1. Energy is lost in overcoming friction.

  2. Overcoming friction is a time consuming process.

  3. Both A and B

  4. None of the above

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Correct Option: A
Explanation:

A lot of the applied energy is lost in overcoming friction so as to put a body in motion.Hence efforts are made to reduce friction.

Why do we sprinkle powder before playing caroms?

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

  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

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Correct Option: B
Explanation:

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

Powder is a lubricant

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

  1. True

  2. False

  3. None

  4. Can't say

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Correct Option: A
Explanation:

Powder is a lubricant because it reduces the friction and makes the surface smooth.

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

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

  1. Powder

  2. Sand

  3. Oil

  4. Water

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Correct Option: C
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.

A car will skid more on a wet road than on a dry one because, between the dry road and the car tyres there is more:

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

  1. Friction

  2. Lubricant

  3. Gravity

  4. Heat

Show answer
Correct Option: A
Explanation:

A vehicle skids on the road due to less friction between the road and the vehicle tyres.