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Jorge is kicking a ball straight up into the air. The height of the ball is described by the equation h=-16t^2+20t, where h is the height of the ball and t is the time in seconds. How long will it take the ball to hit the ground?

Grace_for_Mom  Mar 15, 2017

#1
+5

Use desmos. XD

Or:

I think you should simplify it so that you get 5t-4t2 = 0. After all, when the ball hits the ground, the height should be 0. You can then say, with the above equation, that 5t = 4t2, since adding 4t2 to either side will give you that. Then, you can say that 1.25t = t2, after you divide each side by 4. Divide each side by t, and you get the solution: t = 1.25.

Guest Mar 16, 2017
#1
+5

Use desmos. XD

Or:

I think you should simplify it so that you get 5t-4t2 = 0. After all, when the ball hits the ground, the height should be 0. You can then say, with the above equation, that 5t = 4t2, since adding 4t2 to either side will give you that. Then, you can say that 1.25t = t2, after you divide each side by 4. Divide each side by t, and you get the solution: t = 1.25.

Guest Mar 16, 2017