Hey there! Sign in to join this conversationNew here? Join for free

Edexcel M2 - basic work & energy question (slight confusion) Watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    A particle of mass 14kg is projected vertically upwards from ground level with a speed of 17ms?1. It comes to instantaneous rest at a height of 7m above the ground. As the particle moves it is subject to air resistance of constant magnitude R newtons. Using the work-energy principle, or otherwise, find the value of R.

    do you assume that the total air resistance is 7R? because that's what they have wrote in the solution
    • Thread Starter
    Offline

    0
    ReputationRep:
    bump *****es
    Offline

    2
    ReputationRep:
    The change in an objects kinetic energy + potential energy is equal to the resistive force (excluding deacceleration due to gravity) multiplied by distance travelled:

    Offline

    0
    ReputationRep:
    (Original post by chaz1992)
    The change in an objects kinetic energy + potential energy is equal to the resistive force (excluding deacceleration due to gravity) multiplied by distance travelled
    Sorry this is a bit late, but do you mean
    The change in an objects kinetic energy - potential energy is equal to the resistive force
    and not + potential energy?
    Offline

    2
    ReputationRep:
    (Original post by verdhy)
    Sorry this is a bit late, but do you mean
    The change in an objects kinetic energy - potential energy is equal to the resistive force
    and not + potential energy?
    change in an objects (kinetic energy + potential energy) = work done

    0.5m(v^2-u^2) + mg(h2 - h1) = Work Done; where v is the velocity at h2 and u is the velocity at h1.

    so Change in energy at point A - change in energy at point B = work done.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    What newspaper do you read/prefer?
    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
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

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