What is Friction?
Friction is a force exerted between surfaces of different objects. While force is a well understood concept learnt in the branch of Science called Physics since Primary School, however the understanding of friction is mostly vaguely touched on.
What gives friction?
Imagine that a crate has to be pushed along the surface of a table. Looking between the surfaces under the microscope, one would see irregular surfaces between them regardless of how smooth they might appear to be. The irregular surfaces interlocked with each other, creating some sort of locking action between them that causes the crate hard to push.
Static vs kinetic friction
Something interesting that might be noticed would be this: While it is hard to push an object to get it to start its motion, it is surprisingly easy to continue the object’s motion once it started moving. The answer to the observation would be different friction is acting during different instances.
During the initial pushed, the weight of the object caused the crate to be resting on the surface. This resulted in the interlocking to be more pronounce, giving what is known as static friction. As the name implies, it happens to object that are at rest. The harder you push, the greater will be the static friction as in the graph above. However, does it means that this will increase forever?
Beyond a certain amount of push, the applied force overcome the maximum static friction and the crate starts to move. An abrupt drop in the amount of friction experienced, giving what is known as the kinetic friction.
Applications of friction
In many cases, friction are very useful. A simple action of holding a pen in our hand requires friction to act between these surfaces.
When a person walks, the feet pushes against the ground while friction from the ground prevents the motion of the feet which in turn allowed us to move forward.
Is friction always desire?
Friction causes heat and resulted in wear and tear in most machineries. Although this is inevitable but does poses as a problem in many situations. Therefore, engineers has to think of ways to reduce the amount of friction. One of the way is the use of lubrication.
With the use of lubrication, the gaps between the surfaces are filled. This allows the surface to be smoother, hence reducing the friction between them.
In Summary, friction is an integrate part of our life. Understanding how it works could help us to perform the task at hand. While in instances where it could become undesirable, there are also ways to reduce and prevents failure from occurring.