Observe the speed at which the bodies move relative to different reference systems, for example, a passenger walking

Observe the speed at which the bodies move relative to different reference systems, for example, a passenger walking along a moving train carriage, etc.

A passenger (5 km / h) walking along a train carriage (30 km / h) with his girlfriend in the direction of the train travels at a speed of: 35 km / h relative to the trees outside:
5 km / h in relation to the lining of the train carriage: 0 km / h in relation to his girlfriend.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.