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A creature on the moon throws a rock off a cliff. The height of the rock above the surface of the moon, in meters, t seconds after it is thrown is given by h(t) = −t ^2 + 8t + 10. When does the rock first reach a height of 12 m?

Jul 27, 2022

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If I am correct, h(t) = −t^2+ 8t + 10 so, the rock first reaches the height of 12m at 12 = −t^2+ 8t + 10 and by solving that quadratic we get,

$$T=4±\sqrt{14}$$

So, the rock first reaches the height of 12m at $$4-\sqrt{14}$$ which is aprox 0.25834261 seconds.

Jul 27, 2022