I went for a walk the other day. I went four blocks east, then seven blocks south, then one block west and finally eight blocks north
a. What distance did I travel?
b. What's my displacement?

a) distance is 4+7+1+8=20 blocks

b) displacement is 10 blocks

Explanation:

find displacement: x and y

x axis displacement = 4-1 = 3 blocks

y axis displacement = -7+8= 1 block

displacement = the square root of 3^2 + 1^2

= 9+1 = 10 blocks.

You can find the angle of displacement with respect to the initial position using trig identities, if you wish.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).