To calculate the velocity of an object, the of the position vs time graph should be calculated.

d. platinum would have the greatest temperature increase because it has the lowest specific heat.

the kind of relationship between atmospheric  density and altitude is inverse relationship. this means a surge in either will cut the other factor. density is mass per unit volume, it is hard to compute with only altitude 1,291 kilometers given. also, we could also use temperature and pressure to resolve density but they are not delivered.