1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Average Speed and Average Velocity Question

  1. Sep 4, 2009 #1
    1. To get to a concert in time, a harpsichordist has to drive 124 miles in 2.01 hours.

    (a) If he drove at an average speed of 53.0 mi/h in a due west direction for the first 1.18 h, what must be his average speed if he is heading 30.0° south of west for the remaining 49.8 min?

    (b) What is his average velocity for the entire trip?

    2. Equations:

    avg velocity = Δr/Δt
    avg speed = distance traveled/time of trip

    3. I am completely lost at how to even start this problem..If someone could please guide me in the right direction to solving this, I would greatly appreciate it. Thank you.
  2. jcsd
  3. Sep 4, 2009 #2

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    To illustrate the difference between the two concepts, suppose you drive at 60 mph due west for an hour, turn around in no time flat, and drive at 60 mph due east for another hour. You have come right back to where you started. Your average speed: 60 mph. Your average velocity: 0.

    Think about it as the difference between distance "as a crow flies" and distance as measured by a vehicle's odometer.
  4. Sep 4, 2009 #3
    I understand the concept of the statement that you made, but I am still confused at how to set up this problem.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook