Space flight：練習問題

Rockets are typically launched with a very powerful thrust. According to Newton's Third Law of Motion, what is the action-reaction pair involved in the rocket's propulsion?

A rocket is launched vertically from Earth with its engines providing a constant upward thrust. As the rocket moves higher, it consumes fuel at a steady rate. Neglecting air resistance, which statement best describes the changes in the resultant force acting on the rocket and its acceleration as it climbs towards space?

When a satellite is in a stable Low Earth Orbit (LEO), which description of the forces acting on it is most accurate?

For a rocket launching from Earth to achieve a stable orbit, the rocket must reach a specific minimum velocity known as orbital velocity. If the rocket fires its engines continuously after reaching orbit, what primary change occurs to the rocket's orbit or energy profile?

A spacecraft uses its thrusters in orbit to change direction. In the near-vacuum of space, the thrusters are effective because they exploit which fundamental principle of motion?

When a rocket engine fires, it expels hot exhaust gases out of the back. According to the principle of action and reaction, explain how the motion of these gases results in the upward movement of the rocket.

During space flight, spacecrafts often experience micro-gravity conditions. Explain two distinct challenges this micro-gravity environment poses for astronauts and how these challenges are typically addressed in space missions.

Rockets are designed with a streamlined shape for the initial phase of their journey. Explain why this design is critical during the launch from Earth but becomes unnecessary once the rocket reaches outer space.

The design of a spacecraft is highly specialized to handle the extreme environments encountered during space flight.

a) Rockets are built with a streamlined shape. Explain how this design helps the rocket during its launch through the Earth's atmosphere.

b) Once a spacecraft reaches the vacuum of outer space, explain why it can continue moving at a constant speed even if its engines are turned off, making reference to the forces involved.

c) When returning to Earth, a spacecraft travels at very high speeds through the atmosphere. Why does the exterior of the spacecraft become extremely hot, and what design feature is used to protect the astronauts inside?

A scientific probe is designed for a mission that involves launching from Earth, traveling through space, and eventually returning to Earth.

(a) Rockets are often described as "pushing against the ground" during launch. However, they can still accelerate in the vacuum of outer space where there is no ground or air. Explain how a rocket achieves upward motion in a vacuum using the concept of action and reaction pairs.

(b) The probe has a mass of \(1200\text{ kg}\). Given that the gravitational field strength on Earth is \(10\text{ N/kg}\) and on Mars is \(3.7\text{ N/kg}\), calculate the difference in the weight of the probe between the two planets. Show your steps.

(c) When the probe returns to Earth, it enters the atmosphere at a very high speed. Explain why the spacecraft requires specialized heat insulation tiles and a parachute for a safe landing.

(d) Once in deep space, far from any planets, the probe's engine is turned off. Describe the motion of the probe and explain this behavior using the concept of forces.