Question 1119894
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1.  Write out the function, replacing t with 3.  Do the arithmetic.  You get the height of the flare 3 seconds after the gun was fired.


2.  The general formula is:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  h(t)\ =\ -\frac{1}{2}gt^2\ +\ v_ot\ +\ h_o]


Where *[tex \Large g\ \ ] is the acceleration due to gravity near the surface of planet Earth, *[tex \Large v_o] is the initial velocity of the projectile, and *[tex \Large h_o] is the initial height of the projectile at the instant it was launched.


Since you are using *[tex \Large g\ =\ 9.8], the distance measurements must be in meters and the time in seconds.


So the gun was 2.2 meters above the surface of the water when it was fired.  You have no idea whether the sailor who fired the flare gun was sitting, standing or lying down because you give no indication of the freeboard of the boat, or where his feet were in relation to the waterline of the boat.  Assuming his feet were at or near the waterline, he was probably standing.


3. Same question.  You can convert meters to inches as well as I can.3


4. The maximum height reached by any projectile occurs at time *[tex \Large -\frac{v_o}{g}].  The actual maximum height is the value of the function at that time value.


5.  This was answered as part of the calculation of part 4.


6.  Set the function equal to zero and solve for the positive root.


7.  Set the function equal to 400 and solve for the two roots.  The first will be the time when the flare becomes visible to the other boat and the second root will be the time that it is no longer visible to the other boat.
								
								
John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
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*[tex \LARGE \ \ \ \ \ \ \ \ \ \  
								
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