Turn on thread page Beta
    • Thread Starter
    Offline

    5
    ReputationRep:
    Two particles A and B of mass 5kg and 3 kg respectively are connected by a light inextensible string. Particle A lies on a rough horizontal table and the string passed over a small smooth pulley which is fixed at the edge of the table. Particle B hangs freely. The coefficient of friction between A and the table is 0.5. The system is released from rest. Find
    a) the acceleration of the system
    b) the tension in the string
    c) the magnitude of the force exerted on the pulley by the string

    Why is Pythagoras used for question c) ?
    Offline

    12
    ReputationRep:
    Assuming you can do part (b), you now know the tension in the string. I haven't done the question, so I'll make up an answer - let's suppose it is 10 N. If you were the pulley, what would you feel? You'd feel 10 N acting straight down on you (because of the tension in the part of the string connected to particle B), and 10 N sideways (because of the tension in the part of the string connected to particle A).

    How would you find the resultant of these two forces?
    • Community Assistant
    Offline

    18
    ReputationRep:
    Community Assistant
    Pythagoras is used because the the tension exerted on the pulley points away from the pulley, one vertically and one horizontally and the resultant is the the force exerted on the pulley and the resultant would be the hypotenuse of the triangle.
    • Thread Starter
    Offline

    5
    ReputationRep:
    Thank you so much
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 22, 2017
Poll
Do you think parents should charge rent?
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.