Answer:
time.
Explanation:
Motion can be defined as a change in the location (position) of a physical object or body with respect to a reference point.
This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.
A reference point refers to a location or physical object from which the motion (movement) of another physical object or body can be determined.
Mathematically, the motion of an object is described in terms of acceleration, time, distance, speed, velocity, position, displacement, etc.
A graph can be defined as the graphical representation of data (informations) on horizontal and vertical lines i.e x-axis and y-axis respectively.
A position-time (x-t) graph is a graph of the position of an object against (versus) time.
To make a position-time graph, you should plot the values of the position of an object or body with respect to the starting point on the y-axis against the corresponding time on the x-axis.
Generally, the slope of the line of a position-time (x-t) graph is typically used to determine or calculate the velocity of an object.
An instantaneous velocity can be defined as the rate of change in position of an object in motion for a short-specified interval of time. Thus, an instantaneous velocity is a quantity that can be found by measuring the slope of a line that is tangent to a point on the graph.
In conclusion, the x - t graph also referred to as the position-time graph is used for determining the instantaneous velocity from the slope.
