Problem 2: A stationary motion detector sends sound waves of frequency 1.5 ×105 Hz toward a truck approaching at a speed of 45 m/sec. What is the frequency of the waves reflected back to the detector? 1.95 ×105 Hz

Assume that a person skiing high in the mountains at an altitude of h = 15100 ft takes in the same volume of air with each breath as she does while walking at sea level. determine the ratio of the mass of oxygen inhaled for each breath at this high altitude compared to that at sea level. assume that the air composition (i.e. % of air that is oxygen) is the same at sea level as it is at 15100 ft.

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.

What energy transformations occur each time the skateboarder rolls up the ramp?