Suppose you found a rock that has all of the characteristics of a meteorite. you take it to a physicist friend who confirms that it is a meteorite but says that radioisotope dating indicates an age of only a billion years.
what might be the origin of this meteorite?

The origin might be from MARS

Explanation: Meteorites origin are either from Asteroid, Moon or Mars. Their origin is usually classified according to their age after using radioisotope dating. Meteorites that originate from Mars are between the age of 4.5 billion to 200 million years. Since the meteorite in question is only a billion years old, the origin would be from Mars.

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

50 inches should be the resultant vector