Assignment

1. A brick is thrown upward from the top of a building at an angle of 25° to the horizontal with an initial speed of 15 m/s. If the brick is in flight for 3 seconds, how tall is the building?
2. A fireman 50 m away from a burning building directs a stream of water from the ground-level fire hose at an angle of 30° above the horizontal. If the speed of the stream as it leaves the hose is 40 m/s, at what height will the stream of water hit the building?
3. A stone is projected with a velocity of 5 m/s making an angle of 50° with the vertical.
   • Is there any other angle of projection in the X-Y plane that gives the same range?
   • Calculate the range of the projectile.
   • Draw the trajectory of the projectile.
   • What happens to the time of flight and horizontal range if the motion is performed on the Moon?
4. A boy wants to throw a ball through the window of his house to his friend across the street, which is 80 m wide. The window of the boy’s house is 10 m below the window of his friend’s house. How should he throw the ball?
5. Prove that the gun will shoot three times as high when its angle of elevation is 60° as when it is 30°, but will cover the same horizontal range.