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Stochastic13
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Homework Statement
On a horizontal test track two motors (jet and rocket) are tested. Starting from rest, the rocket motor was accelerated constantly for half the distance of the track and ran the other half at a constant speed. Next, a jet motor was started from rest and finished the whole track with constant acceleration for the entire distance. Both motors covered the same distance in the same time. Show that the ratio of the acceleration of the jet motor to rocket motor is given by: aj/ar = 8/9
Homework Equations
x = xo + vot + 1/2 at^2 where xo and vo are initial distance and velocity respectively
The Attempt at a Solution
I wrote two equations for the distance of each motor. For rocket: x = 1/8 ar*t^2 + v*t/2 and since v*t/2 = ar*t^2/4 we get x = 1/8 ar*t^2 + v*t^2/4 and for the jet motor: x = 1/2 aj*t^2 and set them equal to each-other and find that the ratio is aj/ar = 3/4 instead of 8/9. What am I doing wrong?