Answer completely!
let's say you have an initial velocity of 0 m/s north and a final velocity of 80 m/s north, and it took 5 seconds. what is the acceleration?
okay, now lets say you have a change in velocity of 40 m/s west, and it took 0 seconds, is this even possible? can you have an undefined acceleration, and if so is this considered zero acceleration?

Acceleration = (change in velocity) divided by (time for the change)

-- First case: acceleration= (80m/s north)/(5s)

That's 16 m/s^2 north

-- Second case: acceleration= (40 m/s west) / 0 .

Division by zero is undefined. That does NOT means it's considered anything. It's UNDEFINED, meaning NOT DEFINED ... you can't consider it to be anything.

The fraction indicates 40 divided by zero. The 3rd-grade description of that process is: the number of times you can subtract zero from 40 until the 40 is all gone. It's a very big number. If you need to consider it something, you probably have to use the word "infinity".

One form of Newton's second law of motion reminds us that

Acceleration = (force) / (mass)

If you want acceleration to be huge, then either force must be huge, or mass must be tiny, or both.

In the extreme, the seat of your pants has guided you wisely. It's not even possible. Velocity of anything can't change in zero time.

i think its

where are the vectors ?