Astone is dropped from the roof of a building; 2.00s after that, a second stone is thrown straight down with an initial speed of 25.0m/s, and the two stones land at the same time. how long did it take the first stone to reach the ground? how high is the building? what are the speeds of the two stones just before they hit the ground?

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.