Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    In a simple model of the motion of a car, its velocity vm/s, at time t seconds is given by

    v= (3t^2 -4t +1)i + (5t- 3)j where t is greater than or equal to 0

    a) Find the intial speed of the car.

    b) Find when the car is moving parallel to the vector (i - j)
    Offline

    0
    ReputationRep:
    omg i have no idea
    u dont have enough to do suvat do you?
    Offline

    7
    ReputationRep:
    Wouldnt you put t=0 to find initial speed?

    And then put your v equation equal to (i-j) to find t when moving parallel?

    Im just guessing =/
    Oh god, ive got this soon aswell =/
    Offline

    4
    ReputationRep:
    I guess it starts at t=0

    t=0

    i - 3j = initial velocity

    Initial speed = square root 1^2 + 3^2 = square root of 10



    For parallel to (i - j)

    Velocity will be xi - xj

    3t^2 -4t +1 = -5t +3

    3t^2 + t -2 = 0

    3t^2 +3t -2t -2 = 0

    (3t -2) (t + 1) = 0

    so T = 2/3 or t = -1

    I think????
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 15, 2010
Poll
Do I go to The Streets tomorrow night?
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.