Một cano rời bến chuyển dộng thẳng đều. Thoạt tiên, cano chạy theo hướng Nam – Bắc trong thời gian 2 phút 40 giây rồi tức thì rẽ sang hướng Đông – Tây và chạy thêm 2 phút với vận
tốc như trước và dừng lại. Khoảng cách từ nơi xuất phát đến nơi dừng là 1 km.
Tính vận tốc của cano.

Athin, square metal plate measures 14 cm on each side and has emissivity of 0.60. the plate is heated to a temperature of 745°c. what is the rate at which the plate radiates energy ? the stefan-boltzmann constant is 5.67 × 10-8 w/(m2 ? k4). remember that the plate will radiate energy from both its top and bottom surfaces.

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?

While you are driving in the lane next to the curb on a multi-lane road the car on your left suddenly moves toward you lane. they are about toy crash into your front fender. you