Necesito ayuda con esta pregunta de seleccion multiple: el oxígeno, como uno de los componentes del aire constituye un 21% de su volumen y es necesario para la combustión y la respiración de los seres vivos. la razón por la que es administrado a las personas que vuelan a grandes altitudes es: a. porque hay una mala ventilación debido a los contaminantes del aire que afectan el tracto respiratorio. b. para que se facilite la respiración y se produzca la liberación de energía en el aire. c. para compensar la debilidad de la persona que se expone a altitudes elevadas. d. la baja concentración del gas no permite la respiración normal

thermal energy is the answer

dec 23, 2016 - a load of bricks weighing 680 n a distance of 10 m across a parking lot. if if the worker pushes the cart with a constant force of 209 n, what work= force x distance = 220 n x 10 m = 2200 n.m = 2200 j i don't know where the person got it from, but the initial part, work= force x distance me.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia