Question

what do you meant that the force of friction is a self adjusting force ??
pls answer

Answer 1

Self adjusting force : It means that the opposing value of force changes with the value of force you are applying .

This can be understood by an example
if you are pushing a box on the rough ground .

and you are changing the force you will apply
then don't think that frictional force is applying it's whole value. It will adjust according to your value of force .
if you apply 5 N force frictional force will also apply 5N force in opposite direction.
and if you change your force to 8 N the frictional force will also change to 8 N .

means it means that is self adjusting force .