Solved: A 2540-kg test rocket is launched vertically from

Chapter 5, Problem 5.22

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A 2540-kg test rocket is launched vertically from the launch pad. Its fuel (of negligible mass) provides a thrust force such that its vertical velocity as a function of time is given by v1t2 = At + Bt2 , where A and B are constants and time is measured from the instant the fuel is ignited. The rocket has an upward acceleration of 1.50 m>s 2 at the instant of ignition and, 1.00 s later, an upward velocity of 2.00 m>s. (a) Determine A and B, including their SI units. (b) At 4.00 s after fuel ignition, what is the acceleration of the rocket, and (c) what thrust force does the burning fuel exert on it, assuming no air resistance? Express the thrust in newtons and as a multiple of the rockets weight. (d) What was the initial thrust due to the fuel?