Asled of mass m is coasting on the icy surface of a frozen river. while it is passing under a bridge, a package of equal mass m is dropped straight down and lands on the sled (without causing any damage). the sled plus the added load then continue along the original line of motion. how does the kinetic energy of the (sled + load) compare with the original kinetic energy of the sled? a) it is 1/4 the original kinetic energy of the sled. b) it is 1/2 the original kinetic energy of the sled. c) it is 3/4 the original kinetic energy of the sled. d) it is the same as the original kinetic energy of the sled. e) it is twice the original kinetic energy of the sled.

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.