A witch lifts her cauldron of boiling liquid with a pulley system. Once the cauldron is lifted, liquid issues from two identical holes of cross-sectional area 2,000 mm2 (each) with a velocity of 30 m/s. The liquid sprays 30o below the horizontal. Calculate the force P required to give the cauldron an upward acceleration of 0.5 m/s2 from rest if it contains 40 kg of liquid at the time. The mass of the cauldron itself (when empty) is 20 kg. Assume the density of liquid to be that of water.