(a)what is the min constant accel does the plane need to be airborn(b) how long does it take to become airborn

Question

air craft has a lift off speed of 120 km/h
one dimensional motion with constant accel

re phrased
(a)what minimum constant acceleration does the air craft require if it is to be airborne after a take off run of 240 m

Answer 1

since the distance is 240 m
then
240=.5*a*t^2
and
120=a*t,
solve for t by substituting a*t from the second equation into the first
240=60*t
t= 4 seconds,
then solve for a
120=a*4
a=30 m/s^2

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