Which scenario contributes to increased landing speed for an aircraft?

The correct answer is based on the principles of aerodynamics and how different atmospheric conditions affect aircraft performance. Warm temperatures and high humidity reduce the air density; both of these factors lead to a decrease in lift generated by the wings. To maintain the same lift, an aircraft must increase its speed during landing.

Specifically, when air temperature rises, the air expands and becomes less dense, which means there are fewer air molecules in a given volume of air for the wings to interact with. Furthermore, high humidity means that air contains more water vapor, which also contributes to the reduction in air density. As a result, during landing, the aircraft needs to travel faster to achieve the necessary lift due to this lower density of air.

In contrast, cold temperatures and dry air would increase air density, which can help with lift and potentially reduce landing speed. Normal pressure at sea level typically provides standard conditions where lift and speed calculations are more straightforward, while having a low weight and high angle of attack generally allows for lower landing speeds, as the aircraft can generate the required lift at a slower speed due to less weight and increased lift from the wings at a higher angle of attack.