In watching an airplane take off from a short runway, you overhear someone say he is concerned about the length of the runway because the temperature is so high and the humidity so low. You are not quite sure why these factors should be a cause for concern, so you return to your office and calculate air density at 90°F and 20% relative humidity and at 80°F and 50% relative humidity. You then search the Internet and find that L = Cρu2A, where L is lift (the upward force provided by air flowing over and under a wing), C is a coefficient that depends on wing characteristics, ρ is the density of air, u is the velocity of air over the wing, and A is the wing area. Is the overheard concern justified? Explain your response.