you must design a runway that allows planes to reach a ground speed of 65 m/s before they can take off. If the planes accelerate at 2.5m/s/s, what must the minimum length of the runway be?

  d = 845 m

Explanation:

This is an exercise in kinematics, specifically accelerated motion, let's use the equation

         v² = v₀² + 2 a d

since airplanes start from rest their initial velocity is zero

         v² = 2ad

         d = v2 / 2a

let's calculate

         d = 65² / (2 2.5)

         d = 845 m

this is the minimum distance from the track

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards