A cargo helicopter, descending steadily at a speed of 2.3 m/s, releases a small

Question

A cargo helicopter, descending steadily at a speed of 2.3 m/s, releases a small package. Let upward be the positive direction for this problem. (a) If the package is 71 m above the ground when it is dropped, how long does it take for the package to reach the ground?
1 s

(b) What is its velocity just before it lands? (Indicate the direction with the sign of your answer.)
2 m/s (a) If the package is 71 m above the ground when it is dropped, how long does it take for the package to reach the ground?
1 s

(b) What is its velocity just before it lands? (Indicate the direction with the sign of your answer.)
2 m/s

Explanation / Answer

Part A)

Start with vf^2 = vo^2 + 2ad

vf^2 = (2.3)^2 + (2)(9.8)(71)

vf = -37.4 (negative due to downward direction)

Now apply vf = vo + at

-37.4 = -2.3 + (-9.8)(t)

t = 3.58 sec

Part B)

Solved already in part A

vf^2 = (2.3)^2 + (2)(9.8)(71)

vf = -37.4 (negative due to downward direction)

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