A particle $P$ is launched with speed $20\,\text{m s}^{-1}$ at an angle of $40^\circ$ above the horizontal from point $O$ on level ground.
(i)[2]
Find the height of $P$ above the ground when $P$ has speed $18\,\text{m s}^{-1}$.
(ii)[6]
Calculate the length of time for which the speed of $P$ is less than $18\,\text{m s}^{-1}$, and find the horizontal distance travelled by $P$ during this time.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “By using vertical motion, for example $18^2 - (20\cos40)^2 = -2gh$ or an energy equation” …