Question

______ is a self-adjusting force.

Answer 1

Hint: Define self-adjusting force. It means a force which can adjust itself as required by the situation. It can increase or decrease itself with the change made in the system. Then compare the forces we have with the definition to find out which force works like this.


Complete step by step answer: A self-adjusting force can be defined as a force which can change its magnitude as required in the system.

Static friction is a self-adjusting force.
Static friction comes into play when two objects come in contact with each other. If the surface of two bodies are in contact with each other and we apply a force on one of them, static friction will appear, even if the body is at rest. The static friction will try to make the body to remain at rest. If we apply an external force on the body the static friction will adjust the magnitude to the magnitude of applied force and try to make the object to remain at rest.

So, we can say that static friction is a self-adjusting force because it does not have any fixed magnitude or a fixed direction, but it will adjust the force according to the applied force.
Additional information: The moment when the applied force overcomes the force of static friction, the static friction will reach its limit called the limiting friction.

The value of static friction can be given by the formula,

$f_{\text{static}}\le {\mu }_{s}N$
Where, ${\mu }_s$ is the coefficient of static friction and n is the normal reaction force on the object.

Where maximum static frictional force is,

$f_{\text{static(max)}}={\mu }_{s}N$

We can also say that tension is also a self-adjusting force. If we apply a weight in a string, the tension in the string will be equal to the weight on the string. If we increase the weight, the tension will also increase and it will be equal to the weight. After a limiting weight the string will break but to that point it adjusts with the weight. So, tension is also a self- adjusting force.

Note: Friction is force that will try to resist the motion of a surface moving over another surface.It can work on any surface like two solid surfaces, two fluid layer or it can be two gaseous layers also.Kinetic friction is the frictional force that acts between two moving bodies in contact with each other. Kinetic force is given by,

$f_k={\mu }_{k}N$
Where, ${\mu }_k$ is the coefficient of kinetic friction and n is the normal reaction force on the object.