Mathematics 9709 · AS & A Level · Kinematics of motion in a straight line

Kinematics of motion in a straight line — practice question

A cliff top is $40\text{ metres}$ above sea level. A man in a boat, near the foot of the cliff, is in trouble and launches a distress signal vertically upward from sea level.
(i)[2]

Determine the speed of projection of the signal, given that it rises to $5\text{ m}$ above the top of the cliff.

(ii)[2]

Work out for how long the signal stays above the height of the top of the cliff.

(iii)[3]

The man launches another distress signal vertically upwards from sea level. This second signal remains above the level of the cliff top for $\sqrt{17}\text{ s}$. Determine the speed of projection of the second signal.

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