(a)[2]
Find the speed at which $P$ was projected.
(b)[3]
Find the total length of time for which the speed of $P$ is at least $10\,\text{m s}^{-1}$.
Mathematics 9709 · AS & A Level · Kinematics of motion in a straight line
Kinematics of motion in a straight line — practice question
Particle $P$ is projected vertically upwards from level ground. $P$ attains a maximum height of $45\,\text{m}$. After returning to the ground, $P$ comes to rest and does not rebound.