A model rocket is fired vertically from rest. It has a constant acceleration of 17.5 m/s² for the first 1.5s. Then its fuel is exhausted, and it is in free fall. The rocket has a mass of 87 g; the mass of the fuel is much less than 87 g. Ignore air resistance. 

(a) What was the net force on the rocket during the first 1.5s after liftoff? 

(b) What force was exerted on the rocket by the burning fuel? 

(c) How high does the rocket travel? 

(d) How long after liftoff does the rocket return to the ground? 

(e) Sketch a graph of the rocket's vertical velocity vs. time from launch until it returns to the ground. 

(f) What was the net force on the rocket after its fuel was spent?