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A person riding in a hot-air balloon experiences an upward acceleration of 4.9 m/s². Exactly 2 seconds after the balloon is released from ground level, the person drops a small object. Taking g = 9.8 m/s², find the maximum height above the ground that the dropped object reaches.

1. 14.7 m
2. 19.6 m
3. 9.8 m
4. 24.5 m

Correct answer: 14.7 m

Solution

At t = 2 s the object has an upward velocity of 9.8 m/s and is 9.8 m above the ground. It rises an additional 4.9 m before stopping, giving a maximum height of 14.7 m.

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