physics
posted by John .
An airplane needs at least 145 meters of runway to take off. If the plane starts from rest and accelerates uniformly to a takeoff speed of 170 km/hr then what is its acceleration in meters/second? How long does it take for the plane to become airborne?

First, get everything in the same units. The answer must be in m/sec^2, so we need to convert 170 km/hr to m/sec.
170 km/hr * 1000m/km * hr/3600sec = 47.222m/sec
Now, we know that it takes some time, t, to take off.
v = at
47.222 = at, so
t = 47.222/a
Distance s = 1/2 at^2
145 = 1/2 a (47.222/a)^2 = 2229.938/2a
290a = 2229.938
a = 7.69 m/sec^2
So, checking our answer
t = 47.222/7.69 = 6.14 sec
s = 1/2 * 7.69 * 6.14^2 = 144.955 m
Close enough for jazz.
Respond to this Question
Similar Questions

phys
An airplane must reach a speed of 185 mi/h to take off. If the runway is 500 m long, what is the minimum value of the acceleration that will allow the airplane to take off successfully? 
Physics
An airplane must reach a speed of 240.5 mi/h in order to take off. If the runway is 571.5 m long, what is the minimum value of the acceleration that will allow the airplane to take off successfully? 
physics
To take off from the ground, an airplane must reach a sufficiently high speed. The velocity required for the takeoff, the takeoff velocity, depends on several factors, including the weight of the aircraft and the wind velocity. Part … 
Physics
A jet plane has a takeoff speed of Vto=125km/h (34.72 m/s) and it's engines can power it to accelerate with an average acceleration of 5.6 m/s^2. A.) what length of runway will it need to take off safely? 
Physics
An airplane requires 420 m of runway to take off from an airstrip. If the plane starts from rest and it takes 32 s to lift off, with what velocity does it leave the ground? 
physics
An airplane requires 420 m of runway to take off from an airstrip. If the plane starts from rest and it takes 32 s to lift off, with what velocity does it leave the ground? 
physics
A plane accelerates from rest at a constant rate of 5.00 m/s2 along a runway that is 1800 m long. Assume that the plane reaches the required takeoff velocity at the end of the runway. What is the time tTO needed to take off? 
Science
The airplane can take off when its airspeed (speed of the air flowing over the wing) is equal to 65 knots. What is the length of runway required for the plane to take off if there is a 13 knots head wind? 
physics
the takeoff speed for a large airplane is 180 mi/hr(roughly 80m/s0 the plane is capable of accelerating at a rate of 4m/s^2 assume that the plane starts at rest determine the minimum runway length required for this plane to safely … 
physics
the required takeoff speed for a large airplane is 180mi/hr(80m/s)the plane is capable of accelerating at a rate of 4m/s^2 assume the plane starts at rest, determine the minimum runway length required for this plane to safely take …