If a vehicle traveled 40 km/h in to the city and returned at 60 km/h, what is the average speed for the entire trip?:confused:

Don't know, stumped that's why I am asking

Same problem, different units.

You got 60% on one exam and 40% on the second exam. What is your average score?

Take it step by step...

1. First calculate the total time to go to the city and back. They don't tell you how far the city is, so just use "D" for the distance to the city. The time to travel distance D at velocity V is D/V.

2. Now calculate the average velocity, which remember is distance divided by time. Here the total distance is 2D, and the time you determined in step 1. When you do the division the D's cancel out.


Hope this helps.

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Originally Posted by KeepItSimpleStupid

Same problem, different units.

You got 60% on one exam and 40% on the second exam. What is your average score?

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Nope - different problem entirely. If you just average the velocities you'll get the wrong answer!

Hum ebaines, I'm not sure of that:

Quote:

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Originally Posted by ebaines

Now calculate the average velocity, which remember is distance divided by time. Here the total distance is 2D, and the time you determined in step 1. When you do the division the D's cancel out.

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Does velocity not include displacement, which I believe here is zero since the car returns back?

Average velocity includes displacement, which would be 0 since there is none.

However, average speed, is the total distance traveled