Speed related to Average Velocity

[suessthezeus]

Homework Statement

I am having difficulty thinking about this problem. How is speed related to average velocity?

A car travels along a straight line at a constant speed of 47.0 mi/h for a distance d and then another distance d in the same direction at another constant speed. The average velocity for the entire trip is 33.5 mi/h.

Homework Equations

The Attempt at a Solution

I have been trying to think of it in these terms

(54 + Q) = 33.5

I know this isn't right...can I get some direction

Thanks!

 

[Aquariouse]

Velocity is a vector, meaning that it has a size and direction, speed is a scalar meaning that it only has a size.

Assuming relative values , distance d is equal to distance d, your set up could be:
(47MPH Forward + (X)MPH Forward)/2d = 33.5 Forward

Let d be any real number, in this case the simplest number, one. you would then have:
(47MPH Forward +(X)MPH Forward)/2 = 33.5 Forward
(47MPH Forward +(X)MPH Forward) = 67

Remember if it ask for a vector as a answer you MUST provide direction.

SPOILER: Attempted Soution-
X MPH Forward = 20

 

[Vadermort]

Where does (54+Q) come from? This probably belongs in the relevant equations section.
speed is a scalar quantity, average velocity is a vector
also

A car travels along a straight line at a constant speed of 47.0 mi/h for a distance d and then another distance d in the same direction at another constant speed. The average velocity for the entire trip is 33.5 mi/h.

this isn't asking a clear question, despite it's presence in the problem statement

 

[Aquariouse]

I think he is solving for the second "constant speed"

 

[Vadermort]

Such a kind person so unlike myself XD indeed it was, or seems to be, implicitly there