the law of inertia applies to what kind of objects? Moving, stationary, or both?

Answer 1

Both.

Answer 2

Inertia is a concept that describes the tendency of an object to resist a change in its velocity (i.e. to accelerate). Inertial mass is a measure of this "resistance" and is defined in newton's 2nd law F=ma, where F is the force acting on the object (a vector), a is the objects acceleration (a vector), and m is the inertial mass (a scalar). So objects accelerate only if acted upon by a force, as the lorry stops it is accelerating (changing its velocity) because of the force the road applies to the tires. If no force acts upon objects inside the lorry they will continue to move forward with constant velocity. For example, when we are in a car that stops suddenly our seat belt provides the force to accelerate us to a stop, without the seat belt we would continue to move forward with constant velocity (until something forces us to stop, like the windscreen or steering wheel...) And in a similar fashion unsecured objects will tend to keep moving forward when the lorry stops suddenly (anywhere inside not just in the back). This behavior is in complete agreement with Newton's 2nd law. (which is what I presume is meant by the phrase "law of inertia", there is no "law of inertia")

Answer 3

Both. The law of inertia (aka Newton's First Law) states that an object in motion tends to stay in motion, and an object at rest tends to stay at rest.

Answer 4

both just look in your text book. inertia is the force on and object still or moving it don't matter

Answer 5

An object remains at rest or continues to move in a straight line.
Unless acted upon by external forces.

Answer 6

moving and those at rest