1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Projectile Motion Proof/Hassle

  1. Oct 23, 2006 #1
    This is a real pain and I'm getting nowhere. If you can't see the image look at the attached file.[​IMG]
    Angle a(upper angle)=Theta Angle b(lower angle)=Beta
    Prove these relations:
    a) Rsin2theta+d(1+cos2theta)=(R^2)/Rnot where Rnot= ((vnot)^2)/g
    b) That Rm(meaning maximum R) happens for tan2(thetamax)=Rm/d
    c) 2thetamax+alpha=90 degrees
    d) (Rnot^2)+2dRnot=Rm^2


    For a) I'm getting down to 2costheta(Rsintheta+dcostheta)=(R^2)/Rnot
    But I don't see the next step, maybe I went too far. Or do I need to include Beta somewhere? I don't think I do. There is some trig relation or relating it to the diagram that I just don't see.
    All I really need is help on a)then
    I can use what I know from a) to solve for b) and each one after can be done likewise however I won't get to them if I can't get a) done.
    Please HELP!
     

    Attached Files:

  2. jcsd
  3. Oct 23, 2006 #2

    OlderDan

    User Avatar
    Science Advisor
    Homework Helper

    2costheta(Rsintheta+dcostheta)=(R^2)/Rnot

    R(sinthetacostheta+costhetasintheta)+2dcos^2theta)=(R^2)/Rnot

    Do you remember any trig identities?

    http://www.sosmath.com/trig/Trig5/trig5/trig5.html
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Similar Discussions: Projectile Motion Proof/Hassle
  1. Projectile motion (Replies: 2)

  2. Projectile Motion (Replies: 2)

  3. Projectile Motion (Replies: 1)

Loading...