What Is the Takeoff Speed of an Aircraft Based on a Watch's Angle?

[fuzzy]

Francesca dangles her watch from a thin piece of string while the jetliner she is in takes off from JFK Airport. She notices that the string makes an angle of 25° with respect to the vertical while the aircraft accelerates for takeoff, which takes about 18s. Estimate the takeoff speed of the aircraft.

k so you know that the force of gravity is mg and it's going down, and that the acceleration is ma along the horizontal, and so can you take the tan(25)=a/9.8 to get an acceleration of 4.57m/s^2?

And so for velocity you would get V=Vo+at
V=0+(4.57)(18)
V=82.2m/s?

thanks for reading

 

[andrevdh]

It seems to be correct. Which means the take-off speed is around 300 km/h which is realistic.