Friction, inclined plane and pulleys

Description
The concept of friction is not easy--that is the starting point of the lecture and many of you will agree. At the end of the lecture you will be bound to change your view. All the regular topics like friction on plane surface,inclined plane,motion of a block connected with a pulley on an inclined plane has been dealt with step by step which makes it appear incredibly simple. Using the values obtained by solving a numerical example it has been shown experimentally that friction depends only on nature of surface and not on area or the mass of the object. The most remarkable part of the lecture is the use of air-track through an experiment to show the reduction of friction which is used in hovercrafts and magnev trains. It also shows a rare video of an experiment sold carbon di-oxide is converted to gas and using it friction is reduced .You can see this effect on a video in public content of wiziq named "AMAZING EXPERIMENT--ANY EXPLANATION"