In the horizontal direction, what is the initial velocity of the projectile?

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The discussion focuses on calculating the initial velocity (V) of a horizontally launched projectile, with a flight time of 8 seconds and a 15-degree incline at point B. The correct formulas for determining V, range (R), and height (H) were questioned, with the user attempting to apply incorrect equations. The accurate formulas for projectile motion must be derived from fundamental physics principles, specifically those related to horizontal motion and gravitational acceleration.

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A projectile is launched horizontally at A w/ a speed of V. The time flight is 8 seconds and the path of the projectile at B is inclined by 15 degrees w/ the horizontal.
A. What is the V at A?
B. What is the range?
C. What is the launched height?
https://imgur.com/a/SJjWjuj

I tried solving for V at A using (gt/2sin15) = V.
For range, R = (2sin15cos15V^2)/g
For height, H = V^2(sin^2(15))/2g

Are these the correct formulas?
 
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lolseeker2 said:
Are these the correct formulas?
No. Where did you get these formulas from? If they are not accompanied by some description of the context in which they apply then they are of no use and might as well be ditched.

In the vertical direction, what change of speed would you expect in time t?
 
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