Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    2
    ReputationRep:
    Two particles A and B of mass 4kg and 3kg respectively are connected by a light in extensible string which passes over a smooth fixed pulley. The particles are released from rest with the string taut.

    a) Find the tension in the string

    b) When A has traveled a distance of 2m it strikes the ground and immediately comes to rest

    Assuming that B does not hit the pulley find the greatest height that B reaches above its initial position.


    So i found the tension to part a which is 33.6N

    This is what i did for part b):

    I found the a=1.4ms^2

    For A: u=0 s=2 a=1.4 v=?
    V^2=u^2 +2as
    I got 2.4m/s 2sf

    For B:
    u=2.4 a=1.4 v=0 s=?
    V^2=u^2 +2as
    I got 2.1m

    Can anyone help me identify where i faulted please.
    Offline

    16
    ReputationRep:
    (Original post by Tynos)

    For B:
    u=2.4 a=1.4 v=0 s=?
    V^2=u^2 +2as
    I got 2.1m

    Can anyone help me identify where i faulted please.
    That was a when there was tension pulling the particle upwards

    That tension has gone so a has changed
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by TenOfThem)
    That was a when there was tension pulling the particle upwards

    That tension has gone so a has changed
    How could i find the changed acceleration?
    Offline

    16
    ReputationRep:
    (Original post by Tynos)
    How could i find the changed acceleration?
    You know what the acceleration is

    If you drop a ball what is the acceleration
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by TenOfThem)
    You know what the acceleration is

    If you drop a ball what is the acceleration

    Ahh.. thank you.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by TenOfThem)
    You know what the acceleration is

    If you drop a ball what is the acceleration
    I used 9.8ms^-2 but cannot seem to get 16/7, i get 0.3ms^-2
    Offline

    16
    ReputationRep:
    (Original post by Tynos)
    I used 9.8ms^-2 but cannot seem to get 16/7, i get 0.3ms^-2
    That is motion for part (b)

    How far had it already moved
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by TenOfThem)
    That is motion for part (b)

    How far had it already moved
    Im confused.
    • Study Helper
    Online

    13
    Study Helper
    (Original post by Tynos)
    Im confused.
    You're interested in the greatest height above its initial position.

    This will equal the distance it moved when there was tension in the string, plus the distance it moved up when moving freely under gravity.
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?
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.