To solve for velocity, you should use the formula W = KE, where Work = W, and Kinetic Energy = KE. This is because any work that is done to accelerate an object is converted to the kinetic energy of that object (the work-energy theorem). So, . Plugging in the block's weight (18 kg) and the work done (15 J) will give you a velocity of 1.3 m/s.