## College Physics (4th Edition)

The velocity of the Jeep relative to an observer in the Ford is $130~km/h$ north
Let north be the positive direction. Let $v_{J,r}$ be the velocity of the Jeep relative to the road. $v_{J,r} = 82~km/h$ Let $v_{F,r}$ be the velocity of the Ford relative to the road. $v_{F,r} = -48~km/h$ We can find $v_{J,F}$, the velocity of the Jeep relative to the Ford: $v_{J,r} = v_{J,F}+v_{F,r}$ $v_{J,F} = v_{J,r}-v_{F,r}$ $v_{J,F} = 82~km/h-(-48~km/h)$ $v_{J,F} = 130~km/h$ The velocity of the Jeep relative to an observer in the Ford is $130~km/h$ north