Turn on thread page Beta

M2 OCR question: Circular motion in a hollow sphere watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    Can anyone please help with the attatched question?
    Thanks for any help you can give.
    Attached Images
     
    Offline

    10
    ReputationRep:
    The radius of the circle is rt(5²-3²) = 4m. Take t to be the angle the normal makes with the radius.

    (i)
    R sint = mg
    R (3/5) = 0.5g
    => R = (5/6)g N

    (ii)
    R cost = mv²/r
    (5/6)g (4/5) = 0.5v²/4
    => v =~ 7.23 m/s

    Since v=rw, then:
    w = v/r = 7.23/4 = 1.81 rad/s

    (iii)
    T = 2pi/w = 2pi/1.81 = 3.47 s
    Offline

    0
    ReputationRep:
    (i) this is not correct - sorry i havnt got the formula infront of me, but you just worked out the component of gravity that is acting onto the side of the sphere. you also need to take into account the centripetal force exerted on the particle by the bowl.

    so you need to work out the force of the particle pushing outward, and then find the component of this at normal to the edge of the bowl. you need to add this to the component of gravity.

    correct me if im wrong please, im not completely certain.
    Offline

    10
    ReputationRep:
    I didn't work out the component of gravity. I simply used it to work out the normal reaction exerted by the sphere.
 
 
 
Turn on thread page Beta
Updated: June 22, 2005
The home of Results and Clearing

1,884

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?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

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.