En una clase el profesor pregunta:
¿Qué tipo de sistema es una caja de leche chocolatada sin abrir?
Ana considera que es un sistema aislado y en cambio Martina opina que es un sistema cerrado.
¿Cuál de las dos tiene razón y porqué?
¿Y después de tomarla?

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

What does si stand for, when referring to a system of measurement