Final answer:
The acceleration of the model rocket is 4 m/s², calculated by subtracting the weight from the thrust to find the net force, and then dividing by the mass of the rocket using Newton's second law of motion.
Step-by-step explanation:
The acceleration of a model rocket can be determined by using Newton's second law of motion, which is represented by the formula a = Fnet / m, where a is acceleration, Fnet is the net force acting on the object, and m is the mass of the object.
In this case, the net force (Fnet) on the rocket is the thrust minus the weight of the rocket (since weight acts in the opposite direction to thrust). Thus, Fnet = 35 N (thrust) - 25 N (weight) = 10 N. Therefore, the acceleration a of the rocket is a = 10 N / 2.5 kg = 4 m/s².