O vídeo a seguir apresenta uma propriedade interessantíssima do gás hélio: a superfluidez. O hélio é um gás com temperatura de liquefação muito baixa (próximo a 4,2 K) e não pode ser solidificado com pressões maiores do que 25 atm. Entretanto, em condições específicas, como a do vídeo abaixo, o gás hélio pode se liquefazer e gerar esse fenômeno interessante, em que o líquido "sobe" as paredes do recipiente, contrariando a atração gravitacional. A superfluidez, como chamamos, ocorre em temperaturas abaixo de 2,5 K. Calcule o valor equivalente na escala Celsius para a temperatura em que o estado de superfluidez ocorre.

In a wind tunnel the speed changes as the cross sectional area of the tunnel changes. if the speed in a 6' x 6' square test section is 100 mph, what was the speed upstream of the test section where the tunnel measured 20' x 20'? use conservation of mass and assume incompressible flow. conservation of mass requires that as the flow moves through a path or a duct the product of the density, velocity and cross sectional area must remain constant; i. e., that ova-constant. a model is being tested in a wind tunnel at a speed of 100 mph if the flow in the test section is at sea level standard conditions, what is the pressure at the model's stagnation point? (a) the tunnel speed is being measured by a pitot-static tube connected to a u- tube manometer. what is the reading on that manometer in inches of water? (b) at one point on the model a pressure of 2058 psf is measured. what is the local airspeed at that point?

What type of nuclear decay causes the atomic number of an element to increase by 1?

Which statement best describes copper? a. it has a low resistance and prevents charges from moving freely. b it has a high resistance and allows charges to move freely. c. it has a high resistance and prevents charges from moving freely. d. it has a low resistance and allows charges to move freely