A girl delivering newspapers travels 3 blocks west, 9 blocks north, then 6 blocks east. What is the magnitude of her resultant displacement? Answer in units of blocks.

Answer 1

Her net x-direction (from west to east) displacement is -3 blocks west + 0 + 6 blocks east = +3 blocks

Her net y-direction (from north to south) displacement is 0+ 9 blocks north + 0 = +9 blocks

The magnitude of her resultant displacement is R= sort(3)^2+(9)^2 = 9.48 = 9.5 blocks

Since we are dealing with vectors and direction we must find the angle that the resultant makes with the x-axis ( or eastward direction):

φ=tan^-1(9/3)=tan^-1(3)=71.56 or 71.6 degrees

So the overall resultant displacement is 9.5 blocks at 71.6 degrees N of E

The total distance traveled is 18 blocks.