SOLUTION: a ball is thrown from a height of 15 ft with an initial upward velocity if 5 ft/s. Use the formula h=1 16r2(squared)+vt + s to find out how long it will take for the ball to hit th

Question 195162: a ball is thrown from a height of 15 ft with an initial upward velocity if 5 ft/s. Use the formula h=1 16r2(squared)+vt + s to find out how long it will take for the ball to hit the ground.
thank you.
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

The height function you gave is a little out of whack -- here's what it should be:

Since you want to know what the time (t) will be when the ball hits the ground, what is the height of the ground? How about zero?

In other words we want to know the value of t when h(t) = 0. Substitute the given values for

and

, 5 and 15 respectively, and set the function equal to zero.

Now just solve the quadratic. It doesn't factor over the integers, so your best bet is to use the quadratic formula. You will get two roots but one of them will be negative. You can discard that root because, quite obviously, the ball can't hit the ground before you throw it. The desired time will be equal to the positive root.

John

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