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: Graphical analysis, vx, ax, and xf problems

  1. Sep 20, 2006 #1
    1.) A car travels at 15 m/s for 10s. It then speeds up with a constant acceleration of 2.00 m/s^2 for 15s. At the end of this time, what is its velocity?

    My answer: Vxf= 45 m/s

    2.) An object is moving in a straight line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this time?

    My answer: 39m

    3.) A ball is thrown downward from the top of a building with an initial speed of 25 m/s. It strikes the ground after 2.0s. How high is the building?

    My answer: 30m

    4.) I can't draw a graph on here, so I'll describe it to the best of my abilities. It is a velocity versus(m/s) vs. time (s) graph.

    The graph starts at the origin. At 2.0s, velocity increases 20 m/s. From 2.0 to 4.0 seconds, velocity is constant at 20m/s. From 4.0 to 6.0s, velocity is decreasing by 20 m/s. At 6.0 to 8.0s, velocity is decreasing another 20 m/s.

    question: What is the displacement from 0 to 8.0s?

    My answer: Honestly, I didn't know how to approach this one. All i did was I added up and subtracted...and got 20m.

    5.) Which student used the least precise scale?
    A. 49.06
    B. 49
    C. 50
    D. 49.2
     
  2. jcsd
  3. Sep 20, 2006 #2

    SGT

    User Avatar

    For question 4. Since displacement is the integral of velocity, you should calculate the area under the velocity curve, from 0 to 8 secods.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook