Calculating Constant Acceleration for a Cessna Aircraft Takeoff

[nbroyle1]

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]

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?)

 

[nbroyle1]

After I converted the kilometers per hour to meters per second

 

[collinsmark]

After I converted the kilometers per hour to meters per second

You might want to try that calculation again.

 

[nbroyle1]

thats my problem it should be 44.44m/s

 

[nbroyle1]

thanks

 

[collinsmark]

thats my problem it should be 44.44m/s

Ummm, Try that one more time.

 

[nbroyle1]

i meant 33.33m/s haha

 

[collinsmark]

i meant 33.33m/s haha

That sounds better.