CASE STUDY CHALLENGE

Optimization: Fuel Efficiency Analysis

Overspeeding increases fuel consumption and decreases fuel economy as a result of tyre rolling friction and air resistance. While vehicles reach optimal fuel economy at different speeds, fuel mileage usually decreases rapidly at speeds above 80 km/h.

Fuel Consumption vs Speed Graph

The relation between fuel consumption F (l/100 km) and speed V (km/h) under some constraints is given as:

$$ F = \frac{V^2}{500} – \frac{V}{4} + 14 $$

On the basis of the above information, answer the following questions:

Answer the following:

(i) Find F, when V = 40 km/h. [1]
(ii) Find dF/dV. [1]
(iii)

(a) Find the speed V for which fuel consumption F is minimum.

— OR —

(b) Find the quantity of fuel required to travel 600 km at the speed V at which dF/dV = -0.01.

[2]