Motion in a Straight Line — Chapter Summary

Motion means change in position

Motion means change in position with time. In straight-line motion, position is measured along one chosen axis, and direction is shown by positive or

A body can be treated as

A body can be treated as a point object when its size is much smaller than the distance it moves in a reasonable time.

Instantaneous velocity is defined as

Instantaneous velocity is defined as the limit of average velocity as the time interval becomes infinitesimally small: v = lim_{Δt→0} Δx/Δt = dx/dt. I

Instantaneous speed is the magnitude

Instantaneous speed is the magnitude of instantaneous velocity. It is always equal to the magnitude of velocity at that instant.

Average velocity is displacement divided by

Average velocity is displacement divided by time interval. Average speed is path length divided by time interval. Average speed is greater than or equ