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 circular motion statements

  1. Jun 15, 2010 #1
    1. The problem statement, all variables and given/known data

    Which of the following is not true in relation to an object moving in uniform circular motion?
    a. KE of the object is constant
    b. net force is zero
    c. net work is zero
    d. the magnitude of acceleration is constant
    e. momentum is non-constant


    3. The attempt at a solution

    at first i thought it was e. but then i believe momentum relies on velocity which would not make it true so i believe the best answer is b. but not a 100% sure why
     
  2. jcsd
  3. Jun 15, 2010 #2
    Your choice of B is correct because if there were no forces, the object would travel in a straight line path rather than a circular one, i.e. Newtons 1st Law. The must be some net force that is directed toward the center of the circle which is either tension or some other agency keeping the particle in circular motion. Hope that helps.

    Joe
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook