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dani123
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Homework Statement
A soccer ball is kicked at 38.0° with respect to the horizontal and travels 64.0m before striking the ground.
a) what is its initial velocity?
b) how long was it in the air?
Homework Equations
dv=1/2*at2
dh=Vh*Δt
Kinetic equation d=Vi*t+ 1/2*at2
dh=-V2*sin2θ /g
sinθ=opp/hyp
cosθ=adj/hyp
Δt=-2Vsinθ / g
The Attempt at a Solution
a) dh=cos(38)*64m= 50.4m
dv=sin(38)*64m=39.4m
Find t=√(39.4m/(0.5*9.8))=7.96s
plug this value into the d=Vi*t+ 1/2*at2 equation and solve for Vi if d=64m
Vi=3.14m/s
b) V=dh/Δt= 50.4m/7.96s=6.33m/s
Then solve for Δt=-2Vsinθ / g= 0.80s
I would like for someone to just double check my answers and that I used the appropriate equations and that the number of significant figures are being respected! Thanks so much in advance!