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: Uniform Motion Problems Part.2

  1. May 7, 2006 #1
    Can somebody double check me on this.

    At 5 p.m., Alex rode off from Asteroid. One hour later, Jessica rode off from Asteroid in the opposite direction at a speed 400 kph less than that of Alex. If they were 7900 km apart at 11 p.m., how fast did each travel

    Answer in the form: Alex, Jessica

    Alex rode off at 5 p.m. at x km
    By 11 p.m. (6 hours later), his distance was 6x km

    Jessica rode off at 6 p.m. at x-400 km
    By 11 p.m. (5 hours later), her distance was: 5(x-400) km

    The total distance between them was 7900 km.
    6x + 5(x-400)=7900

    6 x 900 = 5400 (Alex)

    900 - 400= 500 x 5 = 2500 (Jessica)

    5400+2500 = 7900

    So Alex's speed was 900 and Jessica's was 500

    Answered in form 900, 500

    Did i do this correctly? I Know i've posted this problem before but it was in the wrong section. And i solved it the correct way this time i hope...
    Last edited: May 8, 2006
  2. jcsd
  3. May 8, 2006 #2
    The solution is correct.
  4. May 8, 2006 #3
    Man my teacher is a stupid.

    We had a test on this, My answer is Alex - 900 and Jessica - 500. But he says it's wrong. :devil:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook