At point $P$, water leaves the end of a hose pipe with a horizontal velocity of $6.6\,\text{m s}^{-1}$, as shown in Fig. 2.1. The point $P$ is at height $h$ above the ground, and the water lands at point $Q$. The horizontal separation between $P$ and $Q$ is $3.5\,$m. Air resistance is negligible. Between $P$ and $Q$, treat the water as a collection of non-interacting droplets, with only each droplet’s weight acting on it.
(a)[1]
Explain, briefly, why the horizontal component of the velocity of a droplet of water stays constant as it moves from $P$ to $Q$.
(b)[1]
Show that the time for a droplet of water to travel from $P$ to $Q$ is $0.53\,$s.
(c)[2]
Calculate the value of $h$.
(d)[1]
For the motion of a droplet of water from $P$ to $Q$, state and explain whether the droplet’s displacement is less than, greater than or the same as the distance along its path.
(e)[2]
Calculate the magnitude of the displacement of a droplet of water moving from $P$ to $Q$.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “States that the horizontal force on the droplet is zero.” …