Answer:
5 km
Explanation:
displacement is the straight line distance from a particular point. since north and south are in opposite directions, it means that he has taken a u-turn
thus, 10 - 5 = 5km displacement
Answer:

Explanation:
We could use conversation of energy. Total distance the stone will cover will be

the Final velocity will be

Considering that the book is moving with constant speed, the force applied by Anna must be the same that the friction force:

If we clear the previous equation:
Of course steady state condition occurs in almost any system but time it will occurs varies among system. for this kind of system, conduction, steady state conduction occurs when the temperature change from one point to the point is already constant. steady state is not achieved immediately because the heat travels and material will not be heated at the same way at the starting point.
It doesn't mean that the climate is changing, it is probably just the morning dew.