Find the work done when a 20 kg sled is pulled across level ground by a rope that makes a 50 deg angle with the horizontal. The sled moves 40 m and the rope is pulled with 10 N of force. If the work done by friction is 240 J, what will happen to the Kinetic Energy of the sled?

Question

Find the work done when a 20 kg sled is pulled across level ground by a rope that makes a 50 deg angle with the horizontal.  The sled moves 40 m and the rope is pulled with 10 N of force.   If the work done by friction is 240 J, what will happen to the Kinetic Energy of the sled?

drwls · Answer

Work done by rope: W = 10*cos50*40 = 257.1 J If friction uses up 240 J of this work, there are still 17.1 J left to increase the kinetic energy of the sled.