1. The problem statement, all variables and given/known data Work is done when the form of energy changes. Work cannot be done in the absence of motion. Energy conservation law for a projectile (no friction): Potential energy increase equals the kinetic energy decrease. Without friction, and in the absence of external forces, the sum of the potential and kinetic energies of a body is constant. Energy is required to do work. Less power is required while slowly lifting a box than while lifting it up quickly. Problem Weight is: 1 2. Relevant equations 3. The attempt at a solution I thought they were all true except for the first one. But that isn't correct. Thanks!