Question 615821
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What planet are you on?  On planet Earth, near ground level, height in meters at *[tex \LARGE t] seconds after projectile launch is *[tex \LARGE h(t)\ =\ -4.9t^2\ +\ v_ot\ +\ h_o].  Presuming launch from ground level or zero height ON EARTH and a 70 meters per second initial velocity, your particular function must be *[tex \LARGE h(t)\ =\ -4.9t^2\ +\ 70t].  Whatever planet you are talking about must be roughly twice as massive as earth.


Set your function, either the one you have or the correct one, equal to 70 meters.  Solve the resulting quadratic equation.  The smaller number will be the beginning of the desired interval and the larger number will be the end of the desired interval.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
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