Turn on thread page Beta

OCR A2 - textbook further questions A Help watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    thxxx.... got the answer already



    --------------------------------------------------


    can anyone tell me wht to do for this?

    Q4b OCR Physics A2 pg 87

    the distance between the centres of the Earth and the Moon is 3.8*10^8m. Assume that the moon moves in a circular orbit around the centre of Earth. Estimate the period of this orbit to the nearest day. Note that 1 day = 8.6x10^4s

    at first i thought calculating F from newtons law of gravitation then put it into Centripetal force.... but do I have the velocity of the moon???

    how about kepler's 3rd law???

    thxxx
    Offline

    0
    ReputationRep:
    F= GMm/r^2
    a = rw^2

    GMm/r^2 = mrw^2
    GM/r^3 = w^2


    should help, it's where keplers law comes from i thnk
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 27, 2010
The home of Results and Clearing

1,854

people online now

1,567,000

students helped last year

University open days

  1. Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 22 Aug '18
  2. University of Buckingham
    Postgraduate Open Evening Postgraduate
    Thu, 23 Aug '18
  3. University of Glasgow
    All Subjects Undergraduate
    Tue, 28 Aug '18
Poll
How are you feeling about GCSE results day?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.