Q. An airplane requires a longer ground roll to lift-off on hot summer days because
(A) the thrust is directly proportional to free-stream density.
(B) the thrust is directly proportional to weight of the aircraft.
(C) the lift-off distance is directly proportional to free-stream density.
(D) the runway friction is high on hot summer days.
Ans: the thrust is directly proportional to free-stream density.
![Determine the correctness (or otherwise) of the following Assertion [A] and the Reason [R]](https://www.gkseries.com/blog/wp-content/uploads/2023/10/Determine-the-correctness-or-otherwise-of-the-following-Assertion-A-and-the-Reason-R.jpg)
