Khi có sự cố trên đường lái xa hãm phanh để đảm bảo an toàn nên giảm vận tốc từ 75 km/h xuống 45 km/h trên đoạn đường 8,8m.
a) Coi gia tốc xe không đổi, thì nó có giá trị bao nhiêu.
b) Khoảng thời gian cần phanh xe trong trường hợp trên là bao nhiêu?
c) Nếu lái xe tiếp tục phanh xe với gia tốc như lúc đầu, thì bao lâu xe dừng lại kể từ
lúc hãm phanh.

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.