Answer:
in everyday use and in kinematic the speed of an object is the magnitude of the change of its position it is thus a scalar quantity
The frequency of a wave becomes higher due to the object moving at a fast pace coming towards you with shorter wavelengths (depending on the speed) aka the Doppler Effect.
Hope this helps
The answer would be 60 cuz a watetfall is a waterfall
The hierarchy of need was developed by Maslow. The pyramid is a motivational theory in psychology that argues that people is seeking to meet successively higher needs. The base of the pyramid is for the physiological needs to safety, belongingness, esteem, and finaly self-actualization.