In additon to speed, what else should be known to predict the position of a moving body from a given starting point ?

A body starts from rest. What is zero ?

A boy starts running on a straight line path with speed of 20km/h starting from same point. What is the position of the girl w.r.t. boy in 20 minutes?

A body is at rest at x =0 . At t = 0 , it starts moving in the positive x - direction with a constant acceleration . At the same instant another body passes through x= 0 moving in the positive x - direction with a constant speed . The position of the first body is given by x_(1)(t) after time 't', and that of the second body by x_(2)(t) after the same time interval . which of the following graphs correctly describes (x_(1) - x_(2)) as a function of time 't' ?

A body is at rest at x =0 . At t = 0 , it starts moving in the positive x - direction with a constant acceleration . At the same instant another body passes through x= 0 moving in the positive x - direction with a constant speed . The position of the first body is given by x_(1)(t) after time 't', and that of the second body by x_(2)(t) after the same time interval . which of the following graphs correctly describes (x_(1) - x_(2)) as a function of time 't' ?

What is the speed of the body moving with uniform acceleration at the midpoint of two points on a straight line, where the speeds are u and v respectively ?

What is the speed of the body moving with uniform acceleration at the midpoint of two points on a straight line, where the speeds are u and v respectively?