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prosteve037
Joined: 25 Sep 2010 Posts: 6 Location: 222

Posted: Fri Oct 15, 2010 2:51 am Post subject: How Do I Get This Equation? 


Using vy = voy  gt and voy = vosinθ, I can get vy = vosinθ  gt and t = (vy  vosinθ) / g
Eliminating time, t, from the equation y = voyt  .5gt^2, how can I show that vy^2 = vo^2sin^2θ  2gy?
I just can't seem to figure out the algebra here :/
Please help 

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hepcj Site Admin
Joined: 23 Jun 2007 Posts: 125

Posted: Fri Oct 15, 2010 9:43 am Post subject: 


Can you please post the question as written so I can see what information is given.
However, to get the sin (2θ) you would need a cos(θ) somewhere, probably from the xcomponent of velocity since:
sin (2θ) = sin(θ + θ) = cos(θ) sin(θ) + cos(θ) sin(θ)
sin (2θ) = 2 cos(θ) sin(θ) 

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