Dave is scared of flying, especially take-off and landing, because he feels the runway is not long enough. Fran challenges Dave to go up in a small plane if, by arranging formulae, she can prove the runway is long enough for both.
When Dave heads off to the airfield Fran uses vivid graphics to show how to rearrange different formulae.
At the airfield Dave has some speed/time data to gather for Fran. When the data arrives in the studio Fran substitutes them into a formula to work out the acceleration the plane needs to take off. From there she is able to use another formula to work out the length of runway required to take off.
Dave is relieved that the runway at the airfield is three times longer than required for take-off, but will it be long enough for landing?
With one more formula to rearrange it is not long before Fran has proved landing is safe too, and Dave has no choice but to get in the plane.