posted by micky .
Much of the time and expense in drilling an oil well goes into changing the drill bit as it wears out. the drilling pipe must be pulled up and disassembled one section at a time in order to pull the drill bit out of the hole and replace it. A pipe 0.65 miles long weighs 2,400 lbs. it takes the pulling works 7.5s to lift this pipe 20 ft. the height of one section, in order to disassemble. (one horsepower equals 550ft-lb/s)
A. How much work is done in lifting the pipe the length of one section?
B. what is the power delivered by pulling horsepower?