Turn on thread page Beta
    • Thread Starter
    Offline

    7
    ReputationRep:
    A ball is thrown from a point at ground level with velocity 20ms-1 at 30 degrees to the horizontal. The ground is level and horizontal and you should ignore air resistance. Take g to be 10ms-2.

    Find the horizontal distance travelled by the ball before its first bounce.
    • Community Assistant
    Offline

    21
    ReputationRep:
    Community Assistant
    (Original post by Mark Scicluna)
    A ball is thrown from a point at ground level with velocity 20ms-1 at 30 degrees to the horizontal. The ground is level and horizontal and you should ignore air resistance. Take g to be 10ms-2.

    Find the horizontal distance travelled by the ball before its first bounce.
    Resolve the velocity into it's horizontal and vertical components and use SUVAT.
    • Thread Starter
    Offline

    7
    ReputationRep:
    I tried that. I got 20cos30 as the horizontal component and 20sin30 as the vertical component. I tried using s = ut + 1/2at^2, but i dont have s or t.

    Btw, the answer is 35.3.
    • Community Assistant
    Offline

    21
    ReputationRep:
    Community Assistant
    (Original post by Mark Scicluna)
    I tried that. I got 20cos30 as the horizontal component and 20sin30 as the vertical component. I tried using s = ut + 1/2at^2, but i dont have s or t.

    Btw, the answer is 35.3.
    You only get 35.3 if you take g to be 9.8, not 10. So that shouldn't be the right answer given the parameters of the question.

    You know that for the vertical component, you can work out how long the ball is in the air, right? So take:
    u = 20cos30
    a = -10 (assuming + is the upwards direction)
    v = 0
    t = ?

    Now you need to use v = u + at and DOUBLE that answer, because if you don't, it only gives you the time from the ground to the air.

    Then you using the horizontal component, you know there is no horizontal acceleration, but you know how long the ball is in the air for, so take

    s = ?
    u = 20cos30
    a = 0
    t = what you got from the vertical calculation

    then distance = speed * time because acceleration is 0 here, and you should get 34.6, which is the answer if you take g to be 10
    • Thread Starter
    Offline

    7
    ReputationRep:
    thnx so much i got the answer now.
    • Community Assistant
    Offline

    21
    ReputationRep:
    Community Assistant
    (Original post by Mark Scicluna)
    thnx so much i got the answer now.
    You're welcome.

    The best thing to do with these questions is to draw a diagram and do things slowly. I have a mechanical engineering module in my degree and I still do things step by step slowly.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 5, 2017
The home of Results and Clearing

3,587

people online now

1,567,000

students helped last year

University open days

  1. SAE Institute
    Animation, Audio, Film, Games, Music, Business, Web Further education
    Thu, 16 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Fri, 17 Aug '18
  3. University of Bolton
    Undergraduate Open Day Undergraduate
    Fri, 17 Aug '18
Poll
Will you be tempted to trade up and get out of your firm offer on results day?
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.