To determine when the projectile hits the ground, solve 89 – 9.8t = 0 for t. Rounding to the nearest whole second, t is about seconds.

Set the vertical velocity equal to zero and solve: 89 − 9.8t = 0, so 9.8t = 89 and t = 89 ÷ 9.8 ≈ 9.08 seconds. Rounded to the nearest whole second, this is 9 seconds, which is choice A.

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