Question

State two advantages and disadvantages of friction

Answer 1

Hint: Friction opposes sliding of objects against one another. Or it can be said friction comes into play when the body is about to slide. It can stop moving objects. Sometimes it is beneficial for us while sometimes it is unnecessary and unwanted.

Complete Step By Step Solution:

Frictional force is also a contact force. It is exerted when two bodies in contact slide against one another i.e. they have relative motion between them. It exerts in a direction such that it will try to stop sliding between them. Frictional force has some limitations and cannot exceed beyond a value. This can be verified by the fact that an object will move along the ground after a certain time if you slowly increase the force on it from zero. This is because the opposing force which is friction cannot increase after a certain value.

Advantages of friction are:

1.)Friction stops a moving block-
If the block is moving on the floor, the surface of the box in contact with the floor is moving while the floor is at rest so friction will act and oppose the box till it comes to rest.
2.)Asteroids burn in atmosphere before reaching earth-
When asteroids travel toward earth with high velocities, they have to bear a great friction force against them due to the air present in the atmosphere. This friction produces a tremendous amount of heat which eventually burns out the asteroids.

Disadvantages of friction are:

1.)Friction causes less efficiency-
A lot of energy is lost in the form of heat due to friction. So, it wastes a large amount of energy.
2.)Friction causes wear and tear in moving part of machine-
A lot of parts are in contact in a machine, if these push against each other friction starts to act between them and leads to damaging parts.

Note: It is a common misconception that friction always opposes motion. This is completely false. Friction only opposes sliding. For e.g. if two blocks are kept on one another and you slowly push the lower block upper block start to move itself, actually it's friction at work. Since friction would not have acted, the surfaces would have slid against one another. Here friction brings the motion. So, it’s all about the situation. Friction not always opposes motion.