2) Option A.
Force is directly proportional to the mass. As the mass of the fuel deceases as the fuel is burnt, the force also decreases as force is directly proportional to mass, and as the force decreases, the acceleration decreases as acceleration is also directly proportional to the force, and the shuttle may eventually come to a stop due to the increasing deceleration. However, initially if the forces are kept balanced as the space shuttle and the gases exert an equal amount of force on each other in the directions opposite to each other, the object will keep on moving upwards in a constant velocity as the amount of force is also kept constant.
3) Option B.
The motion will definitely change when the forces acting on an object are unbalanced-it will start to move, accelerate or decelerate or change its direction in the direction of the net force. The object will not move at all or continue moving with the same velocity and in the same direction if the forces acting on it are balanced or zero.
4) When the forces are unbalanced and are acting on an object in the same direction, the net force will be found by finding the sum of those forces.
Net force=17+9=26 N.
I really, really hope this helps! And please mark it as brainliest.
