A50-db sound wave strikes an eardrum whose area is 5.0×10−5m2. the intensity of the reference level required to determine the sound level is 1.0×10−12w/m2. 1yr=3.156×107s.

Two cannon balls weighing 18 kg and 24 kg are chained together and fired horizontally with a velocity of 165 m/s from the top of a 21-m wall. the chain breaks during the flight of the cannonballs and the 18-kg cannonball strikes the ground at t = 1.5 s, at a distance of 240 m from the foot of the wall, and 7 m to the right of the line of fire. determine the position of the other cannonball at that instant. neglect the resistance of the air.