Câu 1: Một khẩu súng có khối lượng 4kg bắn ra viên đạn có khối lượng 20g, vận tốc của đạn khi ra khỏi nòng súng là 600m/s thì vận tốc giật lùi của súng là: A. 3 cm/s. B. 12 cm/s. C. 3 m/s. D. 12 m/s.

A1kg cart slams into a stationary 1kg cart at 2 m/s. the carts stick together and move forward at a speed of 1 m/sl. determine whether kinetic energy was conserved in the collision. use the law of conservation of energy to explain the collision

After a big snowfall, you take your favorite rocket-powered sled out to a wide field. the field is 195 m across, and you know that your sled accelerates at a rate of 3.65 m/s2 when the rocket is on. how much time will it take the sled to cross the field starting from rest, assuming the rocket is on the whole time?

The average density of the planet uranus is 1.27 103 kg/m3. the ratio of the mass of neptune to that of uranus is 1.19. the ratio of the radius of neptune to that of uranus is 0.969. find the average density of neptune.