A research capsule of mass m is moved along the following path:
(i) from sea level at the North Pole to sea level at the Equator along the Earth’s surface,
(ii) from the Equator up to a height of 10km in the atmosphere,
(iii) from the same point at the Equator down a mine shaft to a depth of 5km below sea level, and
(iv) from the bottom of the shaft gradually to the centre of the Earth.
a. (a) For each transition listed above, state whether the weight of the capsule increases, decreases, or remains unchanged compared with the previous position, and justify your answer in not more than three sentences per stage.
b. (b) Considering all five positions (starting position plus the four new positions), list them in order of decreasing weight of the capsule, writing a short reason for the extreme (highest and lowest) values.