Answer to Question #229066 in Physics for Bob

Question

How do you do

magnitude of displacement

Answer 1

'Magnitude of displacement' is a technical way of saying 'distance, as measured directly between the start point and the end point'.

As it includes no directional information it is a 'scalar' quantity rather than a 'vector'.

Example, imagine two friends live on opposite sides of a lake. Bill intends to visit Ben. To drive around the edge of the lake is a journey of 20km. To row directly across is a journey of 2km. He doesn't feel like rowing today, so he drives the 20km - but the magnitude of his displacement is still 2km.

This example is constrained to two dimensions. The same principle applies in three dimensions - that is, the magnitude of the displacement is the shortest distance between the two points.