Question

Which of the following describes a situation in which the total distance a hockey player travels is 0 meter from his starting point?

The player skates 0 meter forward and then skates 8 meters in the opposite direction.

The player skates 9 meters forward and then skates 8 meters in the opposite direction.

The player skates 12 meters forward and then skates 0 meter in the opposite direction.

The player skates 12 meters forward and then skates 12 meters in the opposite direction.

Answer 1

the skater skates 12 meters forward then 12 meters in the opposite direction

Answer 2

For this case what we must do is a sum of vectors:
The player skates 12 meters forward:
v1 = 12j
then skates 12 meters in the opposite direction:
v2 = -12j
Adding vectors we have:
v1 + v2 = 12j - 12j
v1 + v2 = 0j
Answer:
The player skates 12 meters forward and then skates 12 meters in the opposite direction.