It takes 25 J of work to pull a 5.0 N object 4.0 m along the floor at constant speed. How much work is done to overcome friction? a. 25 J b. 20 J c. 5.0 J d. 1.3 J

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.