Final answer:
The net force acting on the rocket is calculated by subtracting the force due to gravity (400N) from the upwards thrust force of the rocket engines (1,500N), resulting in a net force of 1,100N upwards.
Step-by-step explanation:
The net force acting on the rocket can be determined by calculating the difference between the upward thrust force and the downward gravity force. Given that the rocket engines produce an upward thrust of 1,500N and that gravity exerts a force of 400N downward, you can subtract the force due to gravity from the thrust to find the net force:
Net Force = Thrust - Force due to Gravity
Net Force = 1,500N - 400N
Net Force = 1,100N
Therefore, the net force acting on the rocket is 1,100N upwards.