Achair of mass 15.0 kg is sitting on the horizontal floor; the floor is not frictionless. you push on the chair with a force of 60.0 n that is directed at an angle of 40.0° below the horizontal, and the chair slides along the floor. use a free-body diagram and newton’s laws to calculate the normal force that the floor exerts on the chair.

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.