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Complex Projectile Motion question. Algebra help needed

by DeerHunter
Tags: algebra, complex, hard, motion, projectile
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DeerHunter
#1
Nov8-10, 06:43 PM
P: 6
1. The problem statement, all variables and given/known data
A cow, with a mass of 327 kg, if fired from a medieval catapault, and travels a horizontal distance of 1375 m. It lands in a depression 39 m below its starting position. If it is launched at an angle of 37.0above the horizontal, find its initial speed.

Givens
HOR
dx= 1375
V1x= ?
ax= 0m/s2
v2x=v1x

VER
dy= -39 m
v1y= ?
ay= -9.81m/s2
v2y=?

T=?


2. Relevant equations
[tex]

x = x_0 + v_0 t + (1/2) a t^2

[/tex]


3. The attempt at a solution
What I did here was make a equation for time of flight for the horizontal
dx=v1*cos37* t +1/2 at^2
1375=v1x*cos37*t
t= 1372/v1*cos37
I then entered this into my vertical distance
dy=v1y*cos37* t +1/2 at^2
-39=v1*sin37*(1372/v1*cos37) + 1/2 (-9.81)(1372/v1*cos37)^2
Now this equation is where it gets tricky, I am not sure how to solve for v1.
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Funkmaster W
#2
Nov8-10, 07:40 PM
P: 13
at that point you should plug in to get rid of sin and cos so you are working with decimals and just follow order of operations. if you have a graphing calculator it would make life much easier but if not just plug and chug and go step by step as to not lose anything.


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