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# The height in ft of a ball after t seconds is given by h=80t-16t^2. how long did it take for the ball to hit the ground

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The height in ft of a ball after t seconds is given by h=80t-16t^2. how long did it take for the ball to hit the ground

Aug 28, 2017

#1
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The height in ft of a ball after t seconds is given by h=80t-16t^2. how long did it take for the ball to hit the ground

The height is equal to zero when the ball is on the ground.

$$\color{red} h=80t-16t^2=0\\ t(80-16t)=0$$

$$t_1=0$$                   The ball is still lying on the ground.

$$80-16t=0\\ 16t=80\\ t=\frac{80}{16}$$

$$t_2=5$$                  The ball has landed.

!

Aug 28, 2017

#1
+8079
+1

The height in ft of a ball after t seconds is given by h=80t-16t^2. how long did it take for the ball to hit the ground

The height is equal to zero when the ball is on the ground.

$$\color{red} h=80t-16t^2=0\\ t(80-16t)=0$$

$$t_1=0$$                   The ball is still lying on the ground.

$$80-16t=0\\ 16t=80\\ t=\frac{80}{16}$$

$$t_2=5$$                  The ball has landed.

!

asinus Aug 28, 2017