Tag: friction

Questions Related to friction

Any substance which is used to reduce the roughness of a surface is called a:

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

  1. Lubricant

  2. Lubrant

  3. Lubrication

  4. None of these

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Correct Option: A
Explanation:

Lubricants reduce the rounghness of an surface and make them smooth. Smooth surfaces have less friction due to reduced roughness.

Friction can be increased by increasing:

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

  1. Smoothness of the surface

  2. Grease on the surface

  3. Roughness of the surface

  4. Lubricating the surface

Show answer
Correct Option: C
Explanation:

Rough surface is uneven so it provides more resisitance to motion of a body hence the frictional force increases.

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

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

  1. muscular force of our body

  2. gravitational pull by earth

  3. frictional force

  4. balanced forces of nature

Show answer
Correct Option: C
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.

In which of the following cases more friction is desirable?

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

  1. Movement of piston in a cylinder

  2. Braking of a vehicle

  3. Running on a track

  4. All of the above

Show answer
Correct Option: B
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.

Spikes are provided in the shoes of athlete

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

  1. For decoration

  2. To increase friction

  3. To decrease friction

  4. None of the above

Show answer
Correct Option: B
Explanation:

Answer is B.

Spikes are provided on the soles of shoes of athletes to increase the friction between the shoe and the ground.

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

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

  1. Increase friction

  2. Decrease friction

  3. Increase pressure

  4. Decrease amount of heat

Show answer
Correct Option: A
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.

Friction reduces efficiency of machines due to:

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

  1. Production of heat

  2. Wearing out of moving parts

  3. Increase in energy consumption

  4. AlI of the above

Show answer
Correct Option: D
Explanation:

Answer is D.

Efficiency is relate to energy conversion performance. A system that can convert energy entirely and completely into energy of another form performs the conversion at 100% efficiency. 
The heat produced by friction cannot be used to recover 100% of the mechanical energy that was converted into heat, the effect of friction is to reduce the (energy conversion) efficiency of machines. 
The parts of the machine wear and tear due to contimuous usage.
More the friction more the enrgy consumption.
Hence, all the options are correct.

_______ is responsible for wear and tear of machine parts.

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

  1. Oil

  2. Steel

  3. Friction

  4. Smoothness

Show answer
Correct Option: C
Explanation:

Friction is responsible for wear and tear of machine parts.
Friction is the main force that is responsible for the wear and tear of machinery, this is why mechanical parts are sometimes oiled, to minimize the friction present.

You are marooned on a frictionless horizontal surface and cannot exert any horizontal force by pushing against the surface. How can you get off?

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

  1. By jumping

  2. By spitting or sneezing

  3. By rolling your body on the surface

  4. By running on the plane

Show answer
Correct Option: B
Explanation:

We will need friction to roll or run on any surface. In our case, we have a frictionless surface. Hence, by conservation of linear momentum sneezing can make us move on that surface.

heat is produced whenever work is done against friction 

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

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Correct Option: A
Explanation:

When friction is present, there is a loss of energy. Since frictional force have done work and the energy is lost. Due to this frictional force is released in the form of heat energy.