Answer:
False
Explanation:
We have never made it to the mantle.
Answer:
40m (40m east)
Explanation:
The fist move is 70m east, and east is the positive direction so the truck initially is at +70m.
The second move is 120m to the west, since east is the positive direction, west must be the negative direction, this means the truck now is at:

The third move is 90m to the east, again, this is the positive direction, so the new position is:

The truck is at + 40m, so it ended up 40m away from its initial position and this is the resultant dispacement.
Assuming that there is in a vacuum, the two object will cool at the same rate, because the objects are made of the same material they will have the same cooling rate, assuming the surrounding temperature is the same.