Question

making connections
aerospace engineers who specialize in propulsion systems for air - and spacecraft utilize newtons three laws of motion. for example, the second and third law of motion are both required for launching a rocket into space. that is because to get a rocket to escape earths gravitational pull, the rocket must experience an upward force that causes it to accelerate.
explain how do newtons second and third law of motion act simultaneously during a rocket launch?
infer when a rocket enters space, newtons three laws of motion act simultaneously. to save fuel, the engines are sometimes turned off, and the rocket moves at a constant velocity. which of newtons three laws of motion applies to this motion of the rocket?
□ newtons first law of motion
□ newtons second law of motion
✓ newtons third law of motion

Explanation:

Step1: Recall Newton's second law

Newton's second law is $F = ma$, where $F$ is the net - force, $m$ is the mass and $a$ is the acceleration. During rocket launch, the burning of fuel creates a downward - directed force (thrust). This thrust is the net - force that causes the rocket (with mass $m$) to accelerate upwards according to $F = ma$.

Step2: Recall Newton's third law

Newton's third law states that for every action, there is an equal and opposite reaction. The rocket expels hot gases downwards (action force). In response, the gases exert an equal and opposite upward force on the rocket (reaction force), which is the thrust that lifts the rocket. So, as the fuel burns and expels gases downwards, the upward reaction force makes the rocket move up while also accelerating it according to the second law.

For the multiple - choice part:
Newton's first law of motion, also known as the law of inertia, states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. When the rocket moves at a constant velocity with the engines turned off in space, there is no unbalanced force acting on it (assuming no external gravitational or frictional forces), and it continues to move with a constant velocity. This is an example of Newton's first law.

Answer:

For the explanation part: The burning of fuel creates a downward - directed thrust (action force according to Newton's third law). The equal and opposite upward reaction force lifts the rocket. At the same time, this upward force causes the rocket to accelerate according to Newton's second law ($F = ma$).
For the multiple - choice part: Newton's first law of motion