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

Kinematics of motion in a straight line — practice question

A particle is launched vertically upwards at a speed of $30\,\text{m s}^{-1}$ from a point on horizontal ground.
(i)[2]

Demonstrate that the particle's greatest height above the ground is $45\,\text{m}$.

(ii)[4]

Determine the time taken for the particle to first reach a height of $33.75\,\text{m}$ above the ground. Also determine the particle's speed at that instant.

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: From $v^2 = u^2 + 2as$ with $v=0$, $u=30$, $a=-g$: $0 = 30^2 + 2(-g)s$

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