Help me please. show the solution and the answer. (make the solution shortest.)

10. A body is projected upward at angle of 30" with the horizontal from a building 20-meter high. Its initial speed is 4 m/'s. Calculate the maximum height! Acceleration of gravity is 10 m/s 1 1. A bullet fired at an angle 0 = 60" with a velocity of 20 m/'s. Acceleration due to gravity is 10 m/s?. What is the time interval to reach the maximum height? 12. An aircraft is moving horizontally with a speed of 50 m/s. At the height of 2 km, an object is dropped from the aircraft. Acceleration due to gravity = 10 m/s', what is the time interval before the object hits the ground