Two highways intersect as shown in Fig. 4-39. At the instant shown, a police car P is distance `d_(p)=800m` from the intersection and moving at speed `v_(p)=80km//h`. Motorist M is

distance `d_(M)=600m` from the intersection and moving at speed `v_(M)=60km//h`. (a) In unit-vector notation, what is the velocity of the motorist with respect to the police car? (b) For the instant shown in Fig. 4-39, what is the angle between the velocity found in (a) and the line of sight between the two cars? (c ) If the cars maintain their velocities, do the answers to (a) and (b) change as the cars move nearer the intersection?

Explanation

(a) `(80km//h)hati-(60km//h)hatj`, (b) 0, ( c) No, they remain unchanged