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.

The passage that directs air to the lungs is called a. diaphragm. b. larynx. c. bronchi. d. pharynx.

Calculate the mass of an object that has a momentum of 100kg x m/sec and velocity of 4 m/sec

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.