2023 SSMO Team Round Problems/Problem 2

Problem

A plane and a car start both move northward. The car moves northbound at 60 miles per hour. The plane moves northeast and increases in altitude at an angle of $30^{\circ}.$ Let $s$ the speed in feet per second that the plane must fly at to move north at the same speed as the car. Find $3s^2$.

Solution

Suppose the plane moves at speed $s$. Its purely horizontal component is then \[\frac{\sqrt{3}}{2}s,\] and the northward part of this horizontal velocity is \[\frac{\sqrt{3}}{2\sqrt{2}}s = 60.\]

Thus, \[\frac{3}{8}s = 3600,\] so \[s = \boxed{9600}.\]

~SMO_Team