Turn on thread page Beta
    • Thread Starter
    Offline

    10
    ReputationRep:
    A jet ski is at the orgini and is travelling due north at 5ms-1 when it begins to accelerate uniformly. After accelerating for 40secs, it is travelling due east at 4ms-1

    The jet ski is travelling south easy t seconds after it leaves the orgini.
    a) find t

    so i wrote down an expression for V,

    v=5j + (0.1i-0125j)t
    = 0.1ti + (5-0125t)j

    then i made them both equal, 5-0.125t = 0.1t (but however the mark scheme says its 5-0.125t = -0.1t)

    i dont get why its -0.1t, please help, thanks
    Offline

    16
    ReputationRep:
    (Original post by Gary)
    A jet ski is at the orgini and is travelling due north at 5ms-1 when it begins to accelerate uniformly. After accelerating for 40secs, it is travelling due east at 4ms-1

    The jet ski is travelling south easy t seconds after it leaves the orgini.
    a) find t

    so i wrote down an expression for V,

    v=5j + (0.1i-0125j)t
    = 0.1ti + (5-0125t)j

    then i made them both equal, 5-0.125t = 0.1t (but however the mark scheme says its 5-0.125t = -0.1t)

    i dont get why its -0.1t, please help, thanks
    because it is SOUTH east, not NORTH east
    • Thread Starter
    Offline

    10
    ReputationRep:
    (Original post by TenOfThem)
    because it is SOUTH east, not NORTH east
    Ohh right... what would happened if its like south west?
    Offline

    16
    ReputationRep:
    (Original post by Gary)
    Ohh right... what would happened if its like south west?
    then both i and j would be negative
    • Thread Starter
    Offline

    10
    ReputationRep:
    (Original post by TenOfThem)
    then both i and j would be negative
    Ah ok, get it now, thanks


    Posted from TSR Mobile
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 5, 2013
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.