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: Speed, velocity and accelaration

  1. Jun 17, 2004 #1
    Just need some help with the following questions which are probably very easy to you guys. Here are the 2 questions I need help with.

    1). A boat sails 150m due south and 150m due east. This takes a total time of 45s. Calculate (i). the boat's average speed and (ii) the boats average velocity.

    2). A car traveling at 10 ms -1 due north speeds up uniformly to a velocity of 25 ms-1 in 5 s. Calculate the acceleration of the car during these 5 seconds. Let the direction of the motion of the car, due north, be taken as the positive (+) direction.

    Thanks in advance.

    Billy. Can email me at: annaporcel@talk21.com
  2. jcsd
  3. Jun 17, 2004 #2


    User Avatar
    Science Advisor
    Homework Helper

    1) Average speed = Total Distance/Total Time = 300m/45s = 6.7m/s
    Average velocity = Total Displacement/Total Time = (150m[south] + 150m[east])/45s
    = 150[itex]\sqrt{2}[/itex]m[south-east]/45s = 4.7m/s[south-east]

    2) a = (v2 - v1)/t = (25 - 10)/5 = 3 m/s -2
  4. Jun 18, 2004 #3

    Thanks very much for your help. Much appreciated.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook