Set 5: Quadratic Equations (Advanced)

Choice B is correct. Choice B is the correct answer. Find vertex: $v = -\frac{-2.4}{2(0.02)} = \frac{2.4}{0.04} = 60$ km/h. At this speed, $T(60) = 0.02(3600) - 2.4(60) + 90 = 72 - 144 + 90 = 18°C$. EV battery thermal management is critical—too hot degrades capacity, too cold reduces efficiency. Manufacturers use quadratic models to optimize cooling systems and speed governors, ensuring batteries stay within safe operating ranges. This mathematical optimization extends battery life and vehicle range, crucial factors in EV adoption and sustainability. Choice A is incorrect because 30 is exactly half the correct value. Choice C is incorrect because 90 is the constant term (baseline temperature), not the optimal speed. Choice D is incorrect because this is double the correct answer.