Finding average speed given two velocities, help

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SUMMARY

The average speed of a person walking from point A to point B at 47.0 m/s and returning at 3.10 m/s is not calculated by simply averaging the two speeds. Instead, the correct method involves determining the total distance traveled and the total time taken for the trip. The average speed is defined as the total distance divided by the total time, which requires calculating the time for each segment of the journey due to the unequal speeds.

PREREQUISITES
  • Understanding of average speed calculation
  • Familiarity with distance, speed, and time relationships
  • Basic algebra for solving equations
  • Knowledge of constant speed motion
NEXT STEPS
  • Calculate total time for the trip using the formula: time = distance/speed
  • Learn about the harmonic mean for averaging speeds in different segments
  • Explore problems involving average speed with varying velocities
  • Review concepts of motion in one dimension
USEFUL FOR

Students studying physics, particularly those focusing on kinematics, as well as educators looking for examples of average speed calculations in real-world scenarios.

steph35
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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...
 
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steph35 said:

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.
 

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