Final answer:
It is false that when reading a grid reference number you read the number first; eastings are read before northings. The displacement for both persons walking in the mentioned problem is the same, making the statement false. It is true that credit cards should be kept away from magnets, and false that one wave's amplitude inherently affects another's.
Step-by-step explanation:
When addressing the question about reading a grid reference, the statement given is false. When reading a grid reference number on a map, you read the eastings (the numbers running from west to east) first and then the northings (the numbers running from south to north). This is also known as the 'along the corridor, up the stairs' method.
In response to the question about displacement, the statement is false. Both individuals will have the same displacement regardless of the order of their movements since displacement is a vector quantity that depends only on the initial and final positions, not on the path taken.
Regarding the critical thinking item about magnetic fields and credit cards, the statement is true. It is recommended to keep credit cards with magnetic strips away from permanent magnets to prevent demagnetization of the strip.
Finally, the statement about wave amplitudes being affected by one another is false. The amplitude of one wave is not affected by the amplitude of another wave unless interferences occur, which happens when waves meet and superimpose on each other.