Question

Friction is a self-adjusting force.
Reason: Friction does not depend upon mass of the body.
A. Both Assertion and Reason is true and Reason is the correct explanation of Assertion.
B. Both Assertion and Reason is true and Reason is not the correct explanation of Assertion.
C. Assertion is true, but Reason is false
D. Both assertion and reason are incorrect

Answer 1

Hint:First start with what is friction and how many types of friction are there. Check whether all types of friction are self-adjusting or not. Then try to find the formula for friction and check on what quantities the value of friction depends. Does it depend on mass or not?.



Formula used
Friction force, \[{F_k} = \mu mg\]\[\]


Complete answer:
First start with what is friction:
As we know friction is the resistance force between an object and surface while the object is moving on the surface.
There are various types of friction we know, such as Static friction, Sliding friction, Rolling friction, Fluid friction. But out of all these only static friction is self-adjusting as in case of static friction, friction is equal and opposite to the applied force on the body or object (before the start of the motion).
Therefore, the Assertion is wrong.
Now, we know that frictional force is given by:
\[{F_k} = \mu mg\]
Where, m is the mass of the object or body in motion.
So, the frictional force depends on the mass of the body.
Therefore, the Reason is also wrong.

Hence, the correct answer is Option D.


Note: Here a general term was used that is friction, if a specific friction was used such as static friction then the Assertion will be right as static friction is self-adjusting. Also friction in general terms in Reason does not matter as all types of friction depends on the mass of the body.