How does newton's first law realte to rocket movement?

Answer 1

Newton's first law, which dictates that objects will maintain their current states of stillness or motion unless acted upon, affect rockets in two ways.

First, it establishes the need to exert a massive force to get a rocket off the ground: not only to simply get moving but also the overcome the force of gravity being exerted on the rocket while on the ground.

Second, it explains why rockets do not need so much thrust once they do get into space. According to the first law, as long as the rocket doesn't have to alter its speed or direction, it doesn't need to exert any more force. This is why space-bound vessels are calculated on such careful trajectories--to allow for their natural tendencies of motion to carry them to their destinations.

Answer 2

The liftoff of a rocket from the launch pad is a good example of this principle. Just prior to engine ignition, the velocity of the rocket is zero and the rocket is at rest. If the rocket is sitting on its fins, the weight of the rocket is balanced by the re-action of the earth to the weight as described by Newton's third law of motion. There is no net force on the object, and the rocket would remain at rest indefinitely. When the engine is ignited, the thrust of the engine creates an additional force opposed to the weight. As long as the thrust is less than the weight, the combination of the thrust and the re-action force through the fins balance the weight and there is no net external force. The rocket stays on the pad. When the thrust is equal to the weight, there is no longer any re-action force through the fins, but the net force on the rocket is still zero. When the thrust is greater than the weight, there is a net external force equal to the thrust minus the weight, and the rocket begins to rise. The velocity of the rocket increases from zero to some positive value under the acceleration produced by the net external force.

As the rocket velocity increases, it encounters air resistance, or aerodynamic drag, which opposes the motion. Drag increases as the square of the velocity. The thrust of the rocket must be greater than the weight plus the drag for the rocket to continue accelerating. If the thrust becomes equal to the weight plus the drag, the rocket continues to climb at a fixed velocity, but it does not accelerate. This flight condition is often encountered by model rockets because of the low thrust and high drag of their design. Full scale rockets usually have sufficient excess thrust to continue accelerating. Drag eventually begins to decrease because drag depends on the air density and density decreases with increasing altitude.

Answer 3

Newton's three laws are general laws for any object in rest or in motion.

The first law states that any object will be at rest or in uniform motion if no net forces are acting on it.

If a rocket moves with uniform speed in a straight line (uniform motion) , it implies that no net force is acting on it.

Answer 4

the rocket pushes on the ground and the force of the fuel igniting pushes the rocket up