Derive P=4T/R from fluid mechanics

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.

Irrigation channels that require regular flow monitoring are often equipped with electromagnetic flowmeters in which the magnetic field is produced by horizontal coils embedded in the bottom of the channel. a particular coil has 100 turns and a diameter of 6.0 m. when it's time for a measurement, a 4.5 a current is turned on. the large diameter of the coil means that the field in the water flowing directly above the center of the coil is approximately equal to the field in the center of the coil. the field is directed downward and the water is flowing east. the water is flowing above the center of the coil at 1.5 m/s . what is the magnitude of the field at the center of the coil? what is the direction of the force on a positive ion in the water above the center of the coil? what is the magnitude of the force on an ion with a charge +e?

A47 kg person in a rollercoaster moving through the bottom of a curved track of radius 47.7 m feels a normal force of 895 n. what is the net centripedal force acting on the person