Position Formula

Position Formulas - Change in Position Formula & Examples

If the position of a point is r1 and the position of another point is r2 with respect to a fixed, Then the position of the first point with respect to second point gives position formula.

Change in position is given by:
                              Δr = r2 - r1

If the change in position is dependent upon time, then the position can be represented as
                             r (t) = ½ at2 + ut + r1
Where a = constant acceleration
            u = initial velocity
            r = initial position.

Example:
A boy who has an initial velocity of 2 m/s had already covered for a distance of 10 m. If it has a constant acceleration of 2 m/s2, find the position of the boy at the end of 5s.
Ans:

Position of the boy = r (t) = ½ at2 + ut + r1
                                          =½ x 2 x 25 + 2 x 5 + 10
                                          = 45m

Question:
A man at a distance of 10m towards east from his home travels some distance to reach a point which is 50 m towards west from his home. Calculate his current position with respect to his home.