Answer Happy

Which statement about the concept of work, as defined in physics, is most correct? 1. A force does work on an object whether

or not the object moves. 2. The component of F perpendicular to the displacement of an object on which it is act- ing always does positive work. 3. Only the component of F parallel to the non-zero displacement of an object does work. 4. A force can only do work on an object if it points in the same direction as the displace- ment of the object. 5. Physicists don't really know what work and energy are; these concepts are widely used but poorly understood. 6. Only the net force F acting on an object does work on the object.