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: Calc. the car's average acceleration

  1. Sep 5, 2007 #1
    Help please :)

    1. The problem statement, all variables and given/known data

    A Car with a velocity of 25m/s[E] changes its velocity to 25m/s in 15s. Calc. the car's average acceleration.

    2. Relevant equations

    Aav= Vf - Vi / T

    3. The attempt at a solution

    I know that the angle is = to 45 degrees S of W since it's a right angle triangle and two sides are equal, therefore, 90 + 45 + 45 = 180.
  2. jcsd
  3. Sep 5, 2007 #2


    User Avatar
    Homework Helper

    You are dealing with vectors here? Do you know how to express the formula you gave with vectors?
  4. Sep 5, 2007 #3
    Yes dealing with vectors. Express the formula with vectors? I don't think so...? I've been learning all this Dx and Dy stuff in class. X-components, y-compenents, sin/cos/tan stuff.
  5. Sep 5, 2007 #4
    Well X and Y components are the axis, or directions North is +Y, South is -Y, East is +X, West -X.

    Just start by making a quick outline of the problem, on a set of axis, that always helps.
  6. Sep 5, 2007 #5


    User Avatar
    Homework Helper

    Are you familiar with this type of notation: [tex]\vec{r} = 34\vec{i} + 25\vec{j}[/tex] (just an arbitrary vector... nothing to do with the problem... i denotes a unit vector in the x-direction... j denotes a unit vector in the y direction)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook