Question

A car travels 30 km north in 25 min. and 40 km east in 35 min. What is the total distance traveled?

Answer 1

The total distance traveled by the car would be the two distances added together.

30 km + 40 km = 70 km

Answer 2

Distance vs Displacement:

The distance traveled is a measure of how much you have been
traveling (whereas displacement measures how far away you are
got from your initial position).

Suppose (for example) that you walk 4 miles from your home to
Walmart, and then walk 4 miles back from Walmart to your house.
Then, altogether you walked: (4 miles) + (4 miles) = (8 miles),
so the distance traveled in this case is 8 miles.

For this case above, the displacement would 0, because you start
at home, and end at home (so your initial and final position is the
same, and whenever your initial and final positions are same, by
definition, the displacement is zero).

Answer 3

Note that the question doesn't ask you to find the Displacement.
In other words, the question doesn't ask you to find "how far are
you now from where you were initially." RATHER, the question is
asking for the total DISTANCE traveled. That is, "how much did you
drive in total" (and not how far did you drive from your initial position)

Answer 4

So, you drove 30 km (to the north), and 40 km (to the east).
How much did you drive overall?

Answer 5

there's a 3 4 5 triangle in this one for the displacement ?

Answer 6

Yes, that is true, for the displacement:)

Answer 7

i suspect that that is part of the thrust of the original q, even though it's not actually in the post.

Answer 8

next up may be average speed etc

Answer 9

Yes, something along those lines:)
(Well, I just help understand the given question ... without assuming anything. Other details might be there to trick ya.)

Answer 10

Well, in any case, hopefully for the person who posted this question, (s)he will come back.

Answer 11

@SolomonZelman Agreed about the return of the phantom poster. I'd be interested to see if the source q is about separating average speed from average velocity. As for "tricks" I'm never quite sure about that. To me, it turns things into crossword puzzles, baffles the "non afficianado" and basically doesn't do physics any favours. A bit like throwing equations and symbols and changing variables. All very "card tricky" maths, but by the time the non maths have hacked through the clever stuff, they may have forgotten the question and the point of the question.

Answer 12

Great responses. I treated this question as if it was asking for distance not discplacement but was a little confused as these types of questions usually ask for discplacement. Its great that you guys provided your thoughts on both. It might help the OP decide which one the question is really asking for.

Answer 13

I would just go after what is said in the question, and if anything (even if the OP gets it wrong), he can tell the instructor "Hey, this is what the question said ...."

Answer 14

The other way around, if you solve for displacement and the correct question turns out to be distance, then you wouldn't have an excuse as to why you didn't solve for distance.

Answer 15

:)

Answer 16

Good thinking :)

Answer 17

@harman.singh yes. treating the q as it stands is vital to the questioner and the answerer. BUT, if the q is to have educational value (which may not be the primary objective, sadly) well that's a diff proposition I think.
Is it "marks fodder" and "exam q fodder" or is it "education" ... ?