Just one sec...
Hey! Sign in to get help with your study questionsNew here? Join for free to post

SUVAT questions.

Announcements Posted on
Take our short survey, £100 of Amazon vouchers to be won! 23-09-2016
    • Thread Starter
    Offline

    0
    ReputationRep:
    I'm having trouble understanding the whole projectiles thing.

    Is g always -9.81 if you consider upwards as positive and downwards as negative?

    If a projectile is thrown horizontally it's just distance/time to find its speed, but if it's thrown at an angle like a javelin is it Fcosx or Fsinx... and even then what have you found?

    Argh!
    Online

    3
    ReputationRep:
    Yes gravity is always that.

    The projectile...you can make a triangle (right-angled)

    and then to find the speed it would be the hypotenuse, and depending on whether you had the vertical or horizontal it would be cos or sin
    • Thread Starter
    Offline

    0
    ReputationRep:
    So when resolving the vertical component it's always time and when resolving the horizontal component it's always distance?
    Offline

    2
    ReputationRep:
    Gravity is negative if you take downwards acceleration to be positive which is the way most people think of it.

    Resolve your velocity into it's horizantal and vertical components, by using trigonometry.

    Then you only need consider the vertical component for how long it's in the air since the horizantal component is not affected by acceleration.

    Just practice some questions.
    Offline

    2
    ReputationRep:
    (Original post by Vicious Fishes)
    So when resolving the vertical component it's always time and when resolving the horizontal component it's always distance?
    In a way yes. But remember it is also travelling a distance vertically. But if it comes back to the same height it was at originally it's vertical displacement is 0 yet it's horizantal displacement may be greater than or equal to 0 (depends what angle it was thrown at).
    • Thread Starter
    Offline

    0
    ReputationRep:
    I think I get it now.

    Thanks.
    Offline

    2
    ReputationRep:
    (Original post by Vicious Fishes)
    I think I get it now.

    Thanks.
    Seriously just go and do a few questions, and then it will make sure it sticks
    Offline

    0
    ReputationRep:
    (Original post by Jooeee)
    Gravity is negative if you take downwards acceleration to be positive which is the way most people think of it.

    Resolve your velocity into it's horizantal and vertical components, by using trigonometry.

    Then you only need consider the vertical component for how long it's in the air since the horizantal component is not affected by acceleration.

    Just practice some questions.
    will g always be negative because some books show both. How much impact would it have on the answer.

    Also how do you know if you need to use horizontal or vertical?
 
 
 
Write a reply…

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: May 28, 2009
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Poll
Who is going to win Bake Off?

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

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