A car initially moves along a straight road at 50 km/hr, and then turns around to travel at 80 km/hr in the opposite direction. What is the car’s change of velocity?

2 answers

change is final minus initial:

-80 - 50 = -130 km/hr
Your answer: 130 km/hr
The change in velocity is the final velocity minus the initial velocity which in this case is adding the 80 km/hr arrow to the negative of the 50 km/hr arrow. This makes both the arrows point in the same direction, so the magnitudes are added together to account for the change in the car’s velocity.