hello chegg please help me to solve the following questions. I tried it so many many times and I do my best to solve this but at the end I am not really sure for my answers. I want to make sure that I got the correct answer. Please provide the correct solutions including the formula and so on. This is very important to me I need to solve this today I hope you can help me to this. Please. Thank you. I really need you please.

. A ball mill having an inside diameter of 12 ft and an inside length of 14 ft is to be used to grind a copper ore. Measurement shows that the distance between the top of the mill and the leveled surface of the ball charge is 6.35 ft. Density of the ball is 290 lb/ft3. A. Calculate the %volume occupied by the grinding balls? B. What is the weight of balls in the mill? C. What is the critical speed of the mill? D. Calculate the proper speed of the mill. E. At what percent of critical speed should the mill operate