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A balloon is moving upward with a velocity of 4 m/s. When it is at height h, a body is gently released from it. If the body reaches the ground in 4 seconds, find the height h of the balloon when the body was released. (Take g = 9.8 m/s²)
- 62.4 m
- 2.4 m
- 78.4 m
- None of these
Correct answer: 62.4 m
Solution
Taking downward as positive, the body has initial velocity -4 m/s (upward). Distance fallen = h = -4*4 + (1/2)*9.8*4² = -16 + 78.4 = 62.4 m.
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