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Please help! I don't understand this question! 19 pts



                                               
                         1.) A projectile launched straight up into the air with an initial velocity of 20 meters per second from a height of 10 meters. How long will it take for the projectile to hit the ground?


a.) Which formula should be used?

h(t) = -4.9t² + vot + ho

h(t) = -16t² + vot + ho


b.) What is the vo?

c.) What is the ho?

d.) Use the Quadratic Formula to solve

Verified Answer :

caylus

Hello,


gravity on earth :g=9.81 m/s²
\(h(t)=-\frac{g*t^2}{2}+v_{0}*t+h_{0}\)
9.81/2≈4.9
\(v_{0}\ is\ initial\ speed\)
\(h_{0}\ is\ initial\ height\)

Answer 1


2)
h(t)=-4.9t²+20t+10

To hit the ground ht(t)=0
==> -4.9t²+20t+10=0
Δ=20²+4410=560=23,6643...²

t=(-20-4√35)/(-4.92)=4,4555...(s)

t=(-20+4√35)/(-24.9)=-0,37391... to exclude (time must be >0)









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