Con lắc lò xo thẳng đứng, vật nặng có khối lượng m = 400 g. Tại thời điểm t = 0, kéo m xuống dưới vị trí cân bằng để lò xo giãn 2,6 cm đồng thời truyền cho m vận tốc 25 cm/s hướng lên ngược chiều dương Ox, lấy
g = 10 m/s2
. Dao động với cơ năng toàn phần E = 25 mJ.
a. Viết phương trình dao động. Chọn gốc tọa độ O là vị trí cân bằng.
b. Tính thế năng đàn hồi cực đại và cực tiểu của lò xo.

There is a theory that indicates that dinosaurs became extinct when about 65 million years ago, a large asteroid hit the earth surface. dust caused by this collision blocked the sunlight reaching the earth's surface and many forms of life became extinct due to the cold. fearing this threat, how large the radius of an asteroid should you be looking for if the dangerous asteroid size is approximately the same as the one that killed the dinosaurs? available data suggests that about 18% of that asteroid's mass ended up as a dust spread evenly over earth after eventually settling out of the upper atmosphere. about 0.0180 g/cm^2 of dust, which is chemically different than the earth's rock, covered the earth's surface. typical asteroids have a density of about 1.9 g/cm^3. now that we know the size of the asteroid, how much energy was released during impact, assuming all of it was just the kinetic energy of the asteroid right before the impact?

The pressure, volume, and temperature of a mole of an ideal gas are related by the equation pv = 8.31t, where p is measured in kilopascals, v in liters, and t in kelvins. use differentials to find the approximate change in the pressure if the volume increases from 14 l to 14.6 l and the temperature decreases from 375 k to 370 k. (round the answer to two decimal places.)

Individuals who live below the poverty line get seriously ill more often than those who do not what could be the hidden variable in this situation?