What is the Average Velocity of a Motorist with Multiple Legs of Travel?

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SUMMARY

The average velocity of a motorist who drives for 35 minutes at 85 km/h, takes a 15-minute break, and then travels 130 km in 2 hours is calculated using the formula v = ∆X/∆t. The total displacement is 180 km, derived from the sum of the distances traveled in both legs of the journey. The total time taken is 170 minutes, leading to an average velocity of approximately 1.06 km/min. This calculation is confirmed as correct despite initial confusion regarding the result.

PREREQUISITES
  • Understanding of basic kinematics, specifically displacement and velocity.
  • Familiarity with the formula v = ∆X/∆t for calculating average velocity.
  • Knowledge of unit conversions, particularly between kilometers and minutes.
  • Ability to perform basic arithmetic operations involving time and distance.
NEXT STEPS
  • Study the concept of average speed versus average velocity in physics.
  • Learn about kinematic equations and their applications in real-world scenarios.
  • Explore problems involving multiple legs of travel to enhance problem-solving skills.
  • Investigate the effects of breaks on average velocity calculations in motion problems.
USEFUL FOR

Students studying physics, particularly those focusing on kinematics and motion analysis, as well as educators looking for practical examples to illustrate these concepts.

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Homework Statement


A motorist drives for 35 minutes at 85km/h and then stops for 15.0 minutes. He then continues traveling 130km in 2 hours. a) What is his total displacement? b) What is his average velocity?


Homework Equations


v= ∆X/∆t (Change in displacement over change in time)


The Attempt at a Solution


I divided 85/km/h and 60 minutes. That makes 1.42 km/m. I timed that by (35) minutes and for the first leg he traveled 49.7km. During the 15 minute break he traveled 0. During the second leg that distance was given (130km). So, 49.7km + 130km gives us the displacement of 180km (roughly).

Now I'm having a hard-time with the average velocity. I use to above formula and get 180km/170minutes (180km is the change in displacement and 170 minutes is the change in time (35m+15m+120m). The answer 1.06km/m seems a little weird to me.
 
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