A protester carries his sign of protest, starting from the origin of

an xyz coordinate system, with the xy plane horizontal. He moves 40

m in the negative direction of the x axis, then 20 m along a perpendicular

path to his left, and then 25 m up a water tower. (a) In unit-vector

notation, what is the displacement of the sign from start to end? (b)

The sign then falls to the foot of the tower.What is the magnitude of

the displacement of the sign from start to this new end?