Hi, not sure how to answer these past HSC questions:
1. Two significant problems that will affect a manned spaceflight to mars are:
- the changes in gravitation energy
- protecting the space vehicle from high-speed electrically charged particles from the sun.
Use your understanding of physics to analyse these problems (8 marks)
2. In 1970 NASA launched Apollo 13, their third mission planned to land humans on the Moon. Half-way to the Moon a huge explosion crippled the spacecraft. The only way home for the astronauts was to fly around the back of the Moon and then fire the rocket engine to take the craft out of lunar orbit and put it into an Earth-bound trajectory
At the completion of the rocket engine burn, mission leader Jim Lovell was heard to say, 'We just put Isaac Newton in the driver's seat.'
Given that the spacecraft returned safely to Earth, justify Jim Lovell's statement (4 marks)
Any help is appreciated, thank you!
Hey f_tan!
That first question you should answer in two parts. The first bit, you are talking about changes in gravitational potential energy. You could (and should) interpret this two ways - The challenge in obtaining that energy, and the challenge in then getting rid of it safely to land on Mars. Your answer to this part of the question should discuss GPE (perhaps include the formula), and discuss the methods by which we can obtain and shed this energy as required. It will likely require a discussion of orbits, as well as the rotational and orbital motion of the earth (think - How do we use the earths rotation to make it easier to gain GPE?)
The second part involving high speed electrically charged particles, you are discussing insulate shielding, much the same as you would discuss in a re-entry into the atmosphere question
The second question is, basically, asking you to explain the Physics principles involved in the described manoeuvre. Essentially what happened is that the spacecraft was crippled while in orbit around the moon. The spacecraft maintained that orbit until a suitable time, where the engines were used to escape that orbit and enter an orbit around the earth (not so much an orbit, but a trajectory, as it had them gradually descend to the surface). Your job in answering the question is to explain how Newton's Laws play a role in that scenario. Newton's law of Universal Gravitation will need mentioning, since that is what governs the nature of orbits, and the 2nd Law (\(F=ma\)) is related to the acceleration of the rocket during the engine burn
I hope that helps