A 21.0 kg shopping cart is moving with a velocity of 4.0 m / s. It strikes a 7.0 kg box that is initially at rest. They stick together and continue moving at a new velocity. Assume that friction is negligible.

What was the momentum of the shopping cart before the collision? 168 kg dot m/s 84.0 kg dot m/s 44.0 kg dot m/s 0 kg dot m/s

What was the momentum of the box before the collision? 84.0 kg dot m/s 0 kg dot m/s 168 kg dot m/s 44.0 kg dot m/s

What is the velocity of the combined shopping cart/box wreckage after the collision? 4.0 m/s 7.64 m/s 2.6 m/s 0 m/s

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.