At the end of most landing runways in airports, an extension of the runway is constructed using a special substance called formcrete. Formcrete can support the weight of cars, but crumbles under the weight of air-planes to slow them down if they run off the end of a runway. If a plane of mass 2.00 x 105 kg is to stop from a speed of 25.0 m/s on a 100-m-long stretch of formcrete, what is the average force exerted on the plane by the formcrete?