Book 23, Question 13
What Happens to the Four Forces During Takeoff, Cruising, and Landing?
A flight has three big parts. Take-off, cruising, and landing. The four forces change in each one! A landing jet touches down at about one hundred fifty miles per hour.
More fun facts
- To start moving down the runway, a plane's thrust must be greater than its drag.
- The plane keeps speeding up until thrust and drag become equal, and then it flies at a steady speed.
- In steady, straight flight, whether level, climbing or descending, the opposing forces cancel each other out.
- In a climb, part of the thrust points upward and helps hold the plane up, while part of the weight pulls backward like extra drag.
- In a glide, part of the weight points forward along the flight path and acts like thrust.
- Right after a small plane touches down, drag from the air is the biggest thing slowing it at first, and brakes work better as it slows and loses lift.
Questions kids ask
Can a plane cruise level at different speeds?
Yes. Flying slowly, the wing must tilt up more to make enough lift, and flying fast, it tilts up less.