A hockey puck is coming towards a hockey player at a velocity of 10 m/s [E]. The player hits the puck with her hockey stick, and the puck leaves her stick with a velocity of 20 m/s [W]. The puck was in contact with the stick for 0.3 s. What was the magnitude of the acceleration of the puck, in m/s²?

Answers within 3% of the true answer will be considered correct.

First Hint: The magnitude of a vector quantity is simply the numerical value with its units of measure, omitting the direction.

Second Hint: The magnitude of a vector is always non-negative (it's either zero or positive).