A car proceeding due south at 60 km/h (V1) makes a right turn, after which it is traveling due west at 80 km/h (V2). What is its change in velocity (V2-V1)?
The Attempt at a Solution
I obviously did 80 km/h - 60 km/h = + 20 km/h. However this is wrong. I don't see why, but it is wrong. The instructor mentioned solving this geometrically or something like that, but I have no clue what they're talking about.