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.

From the graph the speed of the snail in the first 20 seconds centimeter/second. after that, the snail remains in the same place for seconds

Copper has free electrons per cubic meter. a 71.0-cm length of 12-gauge copper wire that is 2.05 mm in diameter carries 4.85 a of current. (a) how much time does it take for an electron to travel the length of the wire? (b) repeat part (a) for 6-gauge copper wire (diameter 4.12 mm) of the same length that carries the same current. (c) generally speaking, how does changing the diameter of a wire that carries a given amount of current affect the drift velocity of the electrons in the wire?

Aray of light traveling parallel to the principal axis of a concave mirror will be reflected through the mirror's