When an object(物体) is being pushed or pulled horizontally, the normal force(法向力) N holding it against the surface it is on is simply its weight mg.
举一反三
- He hurled the statue to the floor with such force that it shattered. A: dropped B: pulled C: pushed D: threw
- A tug is “in irons” when held in a fixed position by（） A: the weight of its tow，its being anchored，or grounded B: the weight of its towing hawser on the bottom C: an adverse current D: lack of power or an engine breakdow
- On this occasion, the company departed from its normal practice of holding the meetings in public.
- The resolution of a microscope refers to () A: Its power to increase an object’s apparent size B: its ability show detail clearly C: its series of interchangeable objective lenses D: its power to scan the surface of an object
- n. the action of one object or surface moving against another; the resistance of one surface to another surface or substance moving over or through it A: gravity B: friction C: hydrogen D: governor