Answer:
A. 85 mph west
Explanation:
Velocity of car 1 is given as
\(v_1 = 35 mph\) towards East
\(\vec v_1 = 35(-\hat i) mph\)
Velocity of car 2 is given as
\(v_2 = 50 mph\) towards West
\(\vec v_2 = 50 (\hat i) mph\)
Now we need to find the speed of car 2 with respect to the frame of car 1
so it is given as
\(\vec v_{21} = \vec v_2 - \vec v_1\)
now we will have
\(\vec v_{21} = 50 (\hat i) - 35 (-\hat i) = 85 \hat i\)
so the relative speed will be 85 mph towards West
