EASY
Earn 100

Define lubricant.

Important Questions on Friction

MEDIUM
Why does a man slip when he steps on a banana peel thrown on the road?
MEDIUM
How will you reduce friction between those machine parts which rub against each other? Give the simplest method.
MEDIUM
When a pencil cell is released from a certain point on an inclined wooden board, it travels a distance of 35 cm on floor A before it comes to rest. When the same pencil cell is released from the same point on the same inclined board, it travels a distance of 20 cm on floor B before coming to rest. Which floor, A or B, offers greater friction? Give reason for your answer.
EASY
Why are lubricants (oil or grease) applied to rubbing surfaces of machines?
EASY
What is meant by lubrication? Why is it important?
MEDIUM
Give examples to show that friction depends on the nature of two surfaces in contact.
 
MEDIUM
Which will cause more friction: a rough surface or a smooth surface? Why?
MEDIUM
Explain why, sportsmen use shoes with spikes.
EASY
Which of the following statements is incorrect?
MEDIUM
Explain with the help of diagrams, how the use of oil reduces friction between two surfaces in contact with each other.
EASY
Explain why, wheels are so useful.
EASY
A boy runs his toy car on dry marble floor, wet marble floor, newspaper and towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be:
EASY
What is meant by ‘rolling friction’?
MEDIUM
You spill a bucket of soapy water on a marble floor accidentally. Would it make easier or more difficult for you to walk on the floor? Why?
MEDIUM
Explain why, it is easier to drag a mat on floor when nobody is sitting on it but much more difficult to drag the same mat when a person is sitting on it.
EASY
Which of the following will produce the maximum friction?
EASY
Why do brake pads of bicycles have to be replaced quite often?