Relative Velocity:
Suppose you are driving a car and you overtake the car in front of you. What actually happens is that the driver from the car behind you sees the car coming in the backward direction and eventually goes back. But the person standing on the ground doesn’t see it as the car is moving backwards, although the driver in that car sees it that way. This is what relative motion and relative veocity is.

Different Types of Waves: Longitudinal & Transverse Waves | Mechanical Wave |

This video explains how food is digested in the human body. It shows how food passes through the digestive tract and how enzymes work on the food to convert complex food into simpler substances.

Adrenaline 3d Animation