Turn on thread page Beta
    • Thread Starter
    Offline

    6
    ReputationRep:
    A golf ball is struck by a golf club from a point on flat, horizontal ground. It leaves the ground at an angle of 40 to the horizontal. 2 seconds after being struck, the ball is travelling upwards at an angle of 10 to the horizontal. Find the speed of projection and the height of the ball above the ground 2 seconds after being struck by the golf club

    The answers are 38.6ms-1 and 30.0m.

    Thanks
    Offline

    20
    ReputationRep:
    where did you get stuck ?
    • Thread Starter
    Offline

    6
    ReputationRep:
    (Original post by the bear)
    where did you get stuck ?
    The part about the 2 seconds and thus the change in angle
    Offline

    20
    ReputationRep:
    the horizontal speed is constant at Vcos40°

    the vertical speed at the start is Vsin40°

    the vertical speed after 2 seconds is Vsin40° -9.8*2

    the ratio of the two speeds is the tan of the angle at that point
    • Thread Starter
    Offline

    6
    ReputationRep:
    (Original post by the bear)
    the horizontal speed is constant at Vcos40°

    the vertical speed at the start is Vsin40°

    the vertical speed after 2 seconds is Vsin40° -9.8*2

    the ratio of the two speeds is the tan of the angle at that point
    "the ratio of the two speeds is the tan of the angle at that point" what does this mean?
    Offline

    20
    ReputationRep:
    (Original post by MastaV)
    "the ratio of the two speeds is the tan of the angle at that point" what does this mean?
    if you divide the vertical component by the horizontal component you get the tan of the angle at which the object is moving.
    • Thread Starter
    Offline

    6
    ReputationRep:
    (Original post by the bear)
    if you divide the vertical component by the horizontal component you get the tan of the angle at which the object is moving.
    This is what I have derived:

    vsin40/vcos40=tan40
    and
    2xvsin40/vcos40=tan10
    Offline

    20
    ReputationRep:
    (Original post by MastaV)
    This is what I have derived:

    vsin40/vcos40=tan40
    and
    2xvsin40/vcos40=tan10
    the first one is right.

    the second one should say

    {Vsin40° -9.8*2 }/Vcos40° = tan10°
    • Community Assistant
    Offline

    19
    ReputationRep:
    Community Assistant
    (Original post by the bear)
    the first one is right.

    the second one should say

    {Vsin40° -9.8*2 }/Vcos40° = tan10°
    Makes me wonder why you're not on the list for Most Helpful Member in Study Help :cute:
    Offline

    20
    ReputationRep:
    (Original post by Mystelle)
    Makes me wonder why you're not on the list for Most Helpful Member in Study Help :cute:
    i know what it is like to struggle with math.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: March 6, 2018
Poll
Cats or dogs?
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.