Final answer:
When trying to move a heavy object, static friction must be overcome to start the motion, which requires more force than kinetic friction, which is what's required to keep the object moving. No work is done if the object doesn't move, despite the force applied. The coefficients of static and kinetic friction vary depending on the materials in contact and surface treatment such as lubrication.
Step-by-step explanation:
The physics behind moving a heavy object across a floor involves understanding static and kinetic friction. Static friction is what keeps the box in place until the force applied exceeds its maximum value. This maximum static friction can be calculated as μsN, where μs is the coefficient of static friction and N is the normal force, which is equal to the weight of the object. Once the object is in motion, kinetic friction is what must be overcome to keep the object sliding, which requires less force than the static friction did. This can be calculated as μkN, where μk is the coefficient of kinetic friction. If the surface is lubricated, such as with oil, it reduces both coefficients of friction, making it easier to move the object.
It's important to note that no work is done if the object does not move, even if a force is applied since work requires displacement. The coefficients of friction depend on the nature of the touching surfaces and are unitless numbers typically ranging between 0 and 1.