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A stone is dropped from the upper observation deck of a tower, 300 m above the ground (Assume g=9.8m/s^2)

If the stone is throw downward with a velocity of 3m/s, how long does it take to reach the ground (round to 2 decimal places).

User AMTourky
by
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1 Answer

3 votes

Answer:

7.45 s

Explanation:

Given:

h₀ = 300 m

g = -9.8 m/s²

v₀ = -3 m/s

h = 0 m


\boxed{h=h_0+v_ot+(1)/(2) gt^2}


0 = 300+(-3)t+(1)/(2) (-10)t^2


0=300-3t-5t^2


5t^2+3t-300=0


\boxed{x=(-b\pm√(b^2-4ac) )/(2a) }


t=(-3\pm√(3^2-4(5)(-300)) )/(2(5))


=(-3\pm√(6009) )/(10)


t=7.45\ s

User Dypbrg
by
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