Question 1197005
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The pilot of a jet transport brings the engines to full takeoff before releasing the brakes 
as the aircraft is standing on the runway. The jet thrust remains constant, and the aircraft has 
a near-constant acceleration of 0.4g. If the takeoff speed is 200 kph, 
calculate the distance s and time t from rest to takeoff.
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<pre>
The acceleration of 0.4g has the value a = 0.4*10 = 4 m/s^2 = 0.004 km/s^2.


The takeoff speed of 200 kph is  v = {{{200/3600}}} m/s = {{{1/18}}} m/s = 0.056 km/s.


Time t to get the takeoff speed of v = 200 kph is

    t = {{{v/a}}} = {{{0.056/0.004}}} = {{{56/4}}} = 19 seconds.    <U>ANSWER</U>


To find the distance, use the formula for rectilinear uniformly accelerated movement

    s = {{{(at^2)/2}}} = {{{(4*19^2)/2}}} = 722 meters.    <U>ANSWER</U>
</pre>

Solved.


The problem teaches you to use the values in consistent units, and to convert units to form, which is required by the formulas.