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Subjects
Science CBSE
Class 8 New
Exploring Forces
Pumpa Practice Questions
13.
Fundamentals of friction
Exercise condition:
5
m.
Choose the correct answer
:
1
.
Why is friction called a contact force?
Because it acts through air without any physical contact
Because it arises only when two surfaces are in direct contact
Because it depends on the mass of the objects involved
Because it acts due to gravitational attraction between objects
2
.
What is the main cause of friction between two solid surfaces?
Interlocking of microscopic irregularities on the surfaces
Heating effect produced due to motion
Chemical reactions occurring between the surfaces
Gravitational force acting on the objects
3
.
Does friction act only between solid surfaces?
Friction acts only when objects move at high speed
Yes, friction acts only between solid objects in contact
No, friction also acts on objects moving through liquids and gases
Yes, friction is absent in liquids and gases
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