題組內容

Question 5. [Maximum mark: 9] 
A water truck tank which is 3 meters long has a uniform cross-section in the shape of a major segment. The tank is divided into two equal parts and is partially filled with water as show in the following diagram of the cross-section. The centre of the circle is O, the angle AOB is ? radians, and the angle AOF β is ? radians629d91f155432.jpg

(c) Calculate the amount of time it will take for the left part of the tank to be fully filled with water. Give your answer in minutes and correct to the nearest integer.