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The equation y = -4.9t^2 + 42t + 18.9 describes the height (in meters) of a ball tossed up in the air at 42 meters per second from a height of 18.9 meters from the ground, as a function of time in seconds. In how many seconds will the ball first reach a height of 84 meters?

 Aug 3, 2022
 #1
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-4.9t^2  + 42t + 18.9  = 84

 

This might be best solved with a graph (in varable x)  here : https://www.desmos.com/calculator/agj3c43ypd

 

It first reaches 84 m  at   t  ≈   2.03  sec

 

 

cool cool cool

 Aug 3, 2022

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