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: Finding force exerted by a rope and ratio of tension:weight

  1. Oct 2, 2011 #1
    1. The problem statement, all variables and given/known data

    A 72.8 kg ice skater is moving at 5.01 m/s when she grabs the loose end of a rope, the opposite end of which is tied to a pole. She then moves in a circle of radius 0.765 m around the pole.

    The acceleration of gravity is 9.8 m/s2 .
    Find the force exerted by the rope on her arms.
    Answer in units of kN = 2.3886108 kN

    Find the ratio of this tension to her weight.

    2. Relevant equations

    Fc = mv^2 / R

    3. The attempt at a solution

    Fc = mv^2 / R
    Fc = (72.8)(5.01)^2 / .765
    Fc = 2388.6108 N
    Fc = 2.3886108 kN

    It's the ratio that's getting me, shouldn't it just be:
    2.3886108 kN / (72.8 x 9.8)

    But the ratio is wrong?

    Please help.
  2. jcsd
  3. Oct 2, 2011 #2
    The ratio is a comparison of two forces. But they must be in the SAME units!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook