Specialist2025 NHT Exam 2 Section A · Q11CAS active1 mark

Time for a drone to fall after stopping

A drone is rising vertically. When it reaches a height of $h$ metres above the ground it is travelling at a speed of $u$ metres per second. At height $h$ metres the drone stops working and it subsequently falls to the ground.

Assuming air resistance is negligible, the time, in seconds, taken for the drone to fall to the ground after it stops working is given by

1 mark

\dfrac{\sqrt{2h}}{g}

\dfrac{\sqrt{2h}}{g}+\dfrac{2u}{g}

-\dfrac{u}{g}+\dfrac{\sqrt{u^2+2gh}}{g}

\dfrac{u}{g}+\dfrac{\sqrt{u^2+2gh}}{g}

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