8.2. Instruction: Answer the questions briefly and concisely. ( Write your answers at the back) 'I. When you are riding in a commercial airplane, it appears that the plane is at rest and the Earth is moving undermeath you. Is this point of view valid? Discuss briefly. 2. How does the elapsed time for a process seem to be longer, an observer moving with the process or observer moving relative to the process? Which observer measures proper time? Explain your answer. 3. How for could you travel into the future without aging significantly? Could this method also applied to travel into the past? 4. To whom does an object seem greater in length, observer moving relative to the object or an observer moving wit the object? Which observer measures the object's proper length? Why