You drive for 30 min for 30 km east and then another 30 min for 40 km north. The magnitude of your average velocity for the entire trip is
A) 40 km/h.
B) 50 km/h.
C) 60 km/h.
D) 70 km/h.
E) 80 km/h.

Question

Quizplus · Accepted Answer

We can use the formula for average velocity:

average velocity = total displacement / total time

First, we need to find the total displacement. Drawing a diagram helps:

```
        N
        |
W------X------>E
        |
        S
```

We start at point X and drive 30 km east to point W. Our displacement is 30 km east.

Then we drive 40 km north to point N. Our displacement is now 30 km east and 40 km north, which we can find using the Pythagorean theorem:

displacement = sqrt(30^2 + 40^2) ≈ 50 km (to 2 decimal places)

Now we need to find the total time. We drove for 30 minutes east and 30 minutes north, for a total of 60 minutes or 1 hour.

Putting it all together:

average velocity = 50 km / 1 h = 50 km/h

So the answer is B.

You Drive for 30 Min for 30 Km East and Then