# I need help in my AP Physics task! ?

### 1 Answer

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- NCSLv 71 month ago
1. At shut off,

h = ½at² = ½ * 20m/s² * (4s)² = 160 m

and v = at = 20m/s² * 4s = 80 m/s

At that point it's simply a rising projectile.

final H = h + v²/(2g) = 160m + (80m/s)² / 19.6m/s² = 487 m

(one might argue for rounding this to 490 m or even 500 m)

2. From H = ½gt² we get

t = √(2H/g) = √(2*487m / 9.8m/s²) = 10 s

3. v = at = 9.8m/s² * 10s = 98 m/s

OR

v = √(2gH) = √(2 * 9.8m/s² * 487m) = 98 m/s

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