# Constant acceleration

A Cessna aircraft has a liftoff speed of 120 km/h.

(a) What minimum constant acceleration does the aircraft require if it is to be airborne after a takeoff run of 250 m?
(b) How long does it take the aircraft to become airborne?

I tried using an equation for constant acceleration and plugged in: .277^2=0+2a(250). When I solved for a I got .000153 and it was incorrect. any suggestions?

collinsmark
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A Cessna aircraft has a liftoff speed of 120 km/h.

(a) What minimum constant acceleration does the aircraft require if it is to be airborne after a takeoff run of 250 m?
(b) How long does it take the aircraft to become airborne?

I tried using an equation for constant acceleration and plugged in: .277^2=0+2a(250). When I solved for a I got .000153 and it was incorrect. any suggestions?
Where did the "0.277" figure come from?

(Edit: And does 27.7 centimeters per second even sound like a reasonable velocity for the liftoff speed of a Cessna aircraft?)

After I converted the kilometers per hour to meters per second

collinsmark
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After I converted the kilometers per hour to meters per second
You might want to try that calculation again.

thats my problem it should be 44.44m/s

thanks

collinsmark
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thats my problem it should be 44.44m/s
Ummm, :uhh: Try that one more time.

i meant 33.33m/s haha

collinsmark
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i meant 33.33m/s haha
That sounds better.