1. The problem statement, all variables and given/known data A cart of mass 5 kg is attached to a block of mass 3 kg by a string that passes over a frictionless pulley. The system is initially at rest and we will assume that friction can be ignored. The block falls a distance of 1 m. What is the work done on the cart by the string during this fall? 2. Relevant equations W= FD W= Change in Kinetic Energy K = mgh 3. The attempt at a solution M=3 G=9.81 H=1 So 3 x 9.81 x 1= 29.43 J But this answer is not correct. What am I doing wrong?