answer the following questions... I'll mark u brain list I will follow u and I'll thank ur answer
Answers
Translate it into english
Answer:
Question 1.
What is the force of friction?
Answer:
The force acting on a moving object equal and opposite to the direction of motion is called force of friction.
Question 2.
What is the cause of friction?
Answer:
The irregularities on the two surfaces in contact is the cause of friction.
Question 3.
What is the force responsible for wearing out of bicycles tyres?
Answer:
Frictional force
Question 4.
Is the friction same for all objects?
Answer:
No
Question 5.
Why are wheels of vehicles made circular?
Answer:
Rolling friction is less than sliding friction.
Question 6.
What is the direction of force of friction acting on a moving object?
Answer:
Opposite to the direction of moving objects.
Question 7.
Why do pieces of luggage fitted with rollers?
Answer:
To reduce friction and to pull them easily.
Question 8.
Why does a matchstick catch fire when rubbed on the rough surface of the box?
Answer:
Due to friction between the stick and rough surface a matchstick catches fire.
Question 9.
What is the name of special shape given to objects moving in fluids?
Answer:
Streamlined
Question 10.
Give one example where ball bearings are used.
Answer:
Ceiling fan
Question 11.
Does friction depend on the nature of objects?
Answer:
Yes
Question 12.
What is the use of lubricants?
Answer:
They are used to reduce friction.
Question 13.
Which surface does produce more friction—smooth or rough surface?
Answer:
Rough surface
Question 14.
Why is fine powder sprinkled on the carrom board?
Answer:
In order to reduce friction powder is sprinkled on carrom board.
Question 15.
Why is it difficult to walk on the wet marble floor?
Answer:
The wet marble floor has less friction. So it is difficult to move on it.
Question 16.
Why does the jar of a mixer become hot when it is run for few minutes?
Answer:
It becomes hot due to friction.
Question 17.
Name the types of friction.
Answer:
Static friction
Sliding friction
Rolling friction
Fluid friction
Question 18.
Which force helps us to write on the paper or blackboard?
Answer:
Frictional force
Question 19.
What is drag?
Answer:
The frictional force exerted by fluids is called drag.
Question 20.
What are fluids?
Answer:
Commonly gases and liquids are called fluids.
Question 21.
Give some examples having streamlined body.
Answer:
Aeroplanes, birds, ships, etc.
Question 22.
Oil, creams and grease are called lubricants. Why?
Answer:
Because they reduce friction.
Question 23.
How can fluid friction be minimised?
Answer:
By giving suitable shapes to bodies moving in fluids.
Question 24.
When does static friction come into play?
Answer:
When we try to move an object at rest, static friction comes into play.
Question 25.
Can we reduce friction to zero?
Answer:
No
Friction Class 8 Extra Questions Short Answer Questions
Question 1.
If we push the book on the table, it stops after sometime. Why?
Answer:
When we push the book on a table, a force is applied on it in the opposite direction of the motion called force of friction. This force opposes the movement and the book stops.
Question 2.
Why are the worn out tyres discarded?
Answer:
The worn out tyres are discarded because their tread are worn off and limiting their effectiveness of providing required amount of friction.