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: Angular Velocity formula

  1. Jul 12, 2007 #1
    1. The problem statement, all variables and given/known data
    a gear of radius 0.4m and a gear of radius 1.2m are connected by a belt. if the smaller gear is rotating with an angular velocity of 10 rad/s,
    find the angular velocity of the larger gear.

    here is the formula: v = rw

    a. what can be said about the linear velocity of a point on the edge of gear 1 and the velocity of the belt?

    b. because it is the movement of the belt that causes gear 2 to turn, what can be said about the linear velocity of a point on the outside of gear 2?

    c. using the linear velocity of the points on the outside of gear 2, found in step b, and the radius of gear 2, find the gear's angular velocity.

    d. what is the relationship between the angular velocity of gear1 and the angular velocity of gear 2?

    2. Relevant equations
    V= RW

    3. The attempt at a solution

    I cannot discover other gear radius or advance through the problem statement, apoligies for my lack of knowledge on this one..
  2. jcsd
  3. Jul 12, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    a) and b) are not formula questions. They are 'use your head' questions. All points on the belt are moving at the same speed. What about points on the gears? How does their speed relate to the speed of the belt?
  4. Jan 19, 2010 #3
    A.) they would be equal
    B.) The linear velocity on the outside of gear 2 should be equal to 4ms. (I think)
    C.) v=rw so 4=1.2w so 2/1.2=w so w=3.333
    D.) 1/3 the speed
    E.) 1. the angular velocity will be greater in gear 2.
    2. the angular velocity will be small in gear 2.
    3. the angular velocity will be equal.

    Plaese fell free to have these answers reviewed/checked. I think we are taking the same problem solving class.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook