PLEASE HELP A bullet is fired from a height of 45 m and hits the ground 2000 m away. With what velocity does the bullet leave the gun?

the answer is 660m/s but I have no idea how to get it.

Asample of a gaseous substance changes into a liquid

Ateam of astronauts is on a mission to land on and explore a large asteroid. in addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. with what minimum initial speed vesc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? assume that the asteroid is approximately spherical, with an average density p 3.84 x108 g/m3 and volume v 2.17 x 1012 m3 recall that the universal gravitational constant is g 6.67 x 10-11 n m2/kg2

Ascrew incorporates which other simple machine? lever wheel and axle inclined plane pulley