Physics 9702 · AS & A Level · Momentum and Newton's laws of motion
Momentum and Newton's laws of motion — practice question
A water jet strikes a vertical wall at right angles, as illustrated in Fig. 3.1. The water reaches the wall with a velocity of $5.0\,\text{m s}^{-1}$ in the horizontal direction. The jet has a cross-sectional area of $1.5 \times 10^{-4}\,\text{m}^2$. The density of the water is $1.0 \times 10^{3}\,\text{kg m}^{-3}$. After impact, the water flows down the wall.
(a)[2]
Demonstrate that, in $1.6\,\text{s}$, the mass of water striking the wall is $1.2\,\text{kg}$.
(b(i))[1]
Calculate the reduction in the horizontal momentum of the mass of water in (a) caused by its collision with the wall.
(b(ii))[1]
Calculate the size of the horizontal force exerted on the water by the wall.
(c)[1]
State and explain the size of the horizontal force exerted on the wall by the water.
(d)[2]
Calculate the pressure exerted by the water on the wall.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Applies $m = \rho V$.” …