Angular relationship question.

AI Thread Summary
The discussion revolves around calculating the horizontal displacement of a model rocket launched at 50 m/s at a 35-degree angle when its velocity vector is at 25 degrees. The user applies kinematic equations and the relationship between sine, cosine, and tangent to derive the equations for vertical and horizontal velocities. However, there is confusion regarding the use of the initial velocity, as the rocket experiences deceleration due to gravity. The calculations lead to a time value that seems incorrect, prompting concerns about the accuracy of the approach. The key issue highlighted is the need to account for the rocket's changing velocity as it ascends and descends.
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Homework Statement


A model rocket is launched at 50m/s, 35 degrees above horizontal. What is the horizontal displacement when its velocity vector is at 25 degrees.


Homework Equations


Kinematic equations, the relationship between sin cos and tan.


The Attempt at a Solution


tan(25)= .4663. I interpret this as the y (sin) velocity being .4663 the x velocity. Vy = .4663Vx

Vy = 50sin(25)-9.8t
.4663Vx = 50sin(25)-9.8t
Vx = (50sin25-9.8t)/.4663
Vx also equals 50*cos25 therefore...
50cos25 = (50sin25-9.8t)/.4663
(.4663*50cos25-50sin25)/-9.8 = t
t = 3.54E^-5.

Something about this answer seems very very wrong, especially when plugged back into the x displacement equation.
 
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Vx also equals 50*cos25 therefore...

Why 50? The rocket decelerated due to gravity.
 

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