A water balloon is observed to emerge from an open window of a gymnasium. The window is 9.5 m above the ground. Through miracles of technology (involving doppler radar and automated video analysis), it is determined that the balloon leaves the window with a speed of 12.5 m/s at an angle of 45∘
45
∘
relative to horizontal.
(A) How much time elapses from when the balloon is passing through the window to when it hits the ground? s
(B) How far from the wall does the balloon hit the ground? m

It is determined that someone within the gymnasium threw the balloon from the floor level of the gymnasium, which is level with the ground outside.
(C) Assuming the launch point is from the floor level, how far from the wall was the balloon launched? m

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.