On the solution of the 6th exercise of the final exam, shouldn't the speed be negative instead of positive?

Well actually a speed has no direction and therefore it makes sense the answer is given as positive. It's just that I would like to be sure I correctly understood the problem. I found a negative speed, meaning the car is actually going in the opposite direction than the plane at 65 mph. In the picture drawn, the car would go from right to left.

Is this correct?

http://ocw.mit.edu/courses/mathematics/18-01sc-single-variable-calculus-fall-2010/final-exam/MIT18_01SCF10_finalsol.pd

Question

On the solution of the 6th exercise of the final exam, shouldn't the speed be negative instead of positive?

Well actually a speed has no direction and therefore it makes sense the answer is given as positive. It's just that I would like to be sure I correctly understood the problem. I found a negative speed, meaning the car is actually going in the opposite direction than the plane at 65 mph. In the picture drawn, the car would go from right to left. 

Is this correct?

http://ocw.mit.edu/courses/mathematics/18-01sc-single-variable-calculus-fall-2010/final-exam/MIT18_01SCF10_finalsol.pd

phi · Answer

yes the car and airplane are heading toward each other.
and as you noted, we use the absolute value of the closing rate (adjusted for the speed of the airplane), because speed is assumed to be a positive quantity.

anonymous · Answer

Ok. Thank you again phi! 

Well, that was my last question on 18.01SC, I'll now move to 18.02SC. :) May I ask how it is that you are so actively involved here for so long? Are you part of some staff?