Finding average speed given two velocities, help

[steph35]

Homework Statement

A person walks first at a constant speed of 47.0m/s along a straight line from point A to point B and then back along the line from B to A at a constant speed of 3.10m/s

Homework Equations

What is her average speed over the entire trip?

The Attempt at a Solution

I tried (4.70m/s + 3.10m/s)/2 to get the average and got 3.9m/s but it was wrong...I can't really think of anything else b/c time isn't given...

 

[LowlyPion]

Homework Statement

A person walks first at a constant speed of 47.0m/s along a straight line from point A to point B and then back along the line from B to A at a constant speed of 3.10m/s

Homework Equations

What is her average speed over the entire trip?

The Attempt at a Solution

I tried (4.70m/s + 3.10m/s)/2 to get the average and got 3.9m/s but it was wrong...I can't really think of anything else b/c time isn't given...

The average speed is the distance traveled divided by time.
Your answer is for equal time intervals at different speeds.
But you have unequal time intervals.
You need to find the total time that it took to go twice the AB distance.

 

[baba89]

As a scientist, it is important to understand that average speed is calculated by dividing the total distance traveled by the total time taken. In this scenario, we can calculate the total distance by adding the distance from A to B (which is the same as the distance from B to A) and the total time by adding the time taken to travel from A to B and back from B to A.

So, the total distance traveled would be 2*(47.0m/s)*t, where t is the time taken for the round trip. Similarly, the total time taken would be t + t = 2t.

Therefore, the average speed can be calculated as (2*(47.0m/s)*t)/(2t) = 47.0m/s.

It is important to note that the units for average speed will be in meters per second (m/s) since we are dividing distance (m) by time (s).

In summary, the average speed for this scenario is 47.0m/s. It is crucial to understand the concept of average speed and how it is calculated in order to accurately solve problems like this. Additionally, it is important to always include units in your calculations and final answer to ensure accuracy.