A sports-car advertisement claims a maximum speed of 250kmh−1. Answer the questions that follow.
a. (i) Express this speed in ms−1.
b. (ii) Express the same speed in cms−1.
c. (iii) Calculate the percentage change in the numerical value of the speed when the unit is changed
(a) from kmh−1 to ms−1, and
(b) from ms−1 to cms−1. Explain the sign of the percentage change in each case.