Ccold air is denser than warm air. when a cold air mass moves into a warm air mass, causing a cold a cold front, the warm air mass is a. squeezed downward, causing clouds and rain b. wedged upward, where its water vapor c. forced backward, as the approaching cold air replaces it d. compressed into a smaller mass, as it becomes even warmer which of these best explains the reason that thunderstorms are likely to form on a hot day? a. warm, humid air rises quickly and then cools b. as air slowly rises it loses humidity and causes rain c. the air is usually calm and allows the clouds to form d. the air rises quickly and forms low-level cloud layers

Two vectors are shown. which statement best compares the vectors? vector x has greater magnitude than vector y. vector y has greater magnitude than vector x. the vectors have the same displacement. the vectors have the same direction.

The a992 steel rod bc has a diameter of 50 mm and is used as a strut to support the beam. determine the maximum intensity w of the uniform distributed load that can be applied to the beam without risk of causing the strut to buckle. take f. s. = 2 against bucklin

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.