Physicshard · Past Paper
A balloon is at a height of 81m and is ascending with a velocity of 12 m/s. A body is dropped from it. If g=10, the body reaches ground in:
A4.05 s
B5.4 s
C6 s
D1.5 s
✓ Correct Answer: B — 5.4 s
-81 = 12t - 5t^2 => 5t^2 - 12t - 81 = 0. Solving the quadratic gives t = 5.4s.
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