Suppose that lisa walks her dog around the block for a little exercise. the block is 1 mile around. if she walks around the block once, what is her displacement? what is her distance?

Displacement only measure how far between the starting and ending point. In this case, Lisa walks around the block as a circle so the starting point is the same as the ending point. Thus, displacement is 0mile.
On the other hand, distance measures exactly how far she walks. In this case, the distance is 1 mile, same as the perimeter of the block.