A missile silo is used to launch test rockets vertically upward out of the silo, giving the rocket an initial speed of 79.4 m/s at ground level. As the rocket clears the silo, the engines fire, and the rocket accelerates upward at 3.80 m/s until it reaches an altitude of 920 m. At that point its engines fail, and the rocket goes into free fall, with an acceleration of -9.80 m/s. (You will need to consider the motion while the engine is operating and the free-fall motion separately. Due to the nature of this problem, do not use rounded intermediate values in your calculations-including answers submitted in WebAssign.) (a) Determine the velocity of the rocket (in m/s) at the end of the engine burn time and also the burn time (in s). (For the velocity, indicate the direction with the sign of your answer.) velocity at end of engine burn time engine burn time V = t = m/s S (b) Determine the maximum altitude of the rocket (in m) and the total time (in s) for the rocket to reach this altitude from ground level. maximum altitude time to reach maximum altitude y = t = m S (c) Determine the rocket's velocity (in m/s) just before ground impact and its total time of flight (in s). (For the velocity, indicate the direction with the sign of your answer.) velocity just before ground impact m/s total time of flight v = t = S