Answer the following with reference to one–dimensional motion along a straight line.
(i) Define the terms (a) distance, (b) displacement, (c) speed, (d) velocity, (e) instantaneous speed and (f) instantaneous velocity.
(ii) State the SI unit of each quantity defined in part (i).
(iii) Categorise each quantity of part (i) as scalar or vector and give one reason for your choice in each case.
(iv) Write any two essential differences between instantaneous speed and instantaneous velocity.