| Exam Board | Edexcel |
|---|---|
| Module | M4 (Mechanics 4) |
| Year | 2002 |
| Session | January |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Vectors Introduction & 2D |
| Type | River crossing: perpendicular heading or minimum time (find drift and/or time) |
| Difficulty | Moderate -0.8 This is a straightforward relative velocity problem requiring basic vector decomposition. The swimmer crosses 'as quickly as possible' (meaning perpendicular to banks in still water), making this a standard 2-step calculation using Pythagoras with clearly given values. Simpler than average A-level mechanics questions which typically require more problem-solving or multi-stage reasoning. |
| Spec | 1.10h Vectors in kinematics: uniform acceleration in vector form3.02a Kinematics language: position, displacement, velocity, acceleration |
A river of width 40 m flows with uniform and constant speed between straight banks. A swimmer crosses as quickly as possible and takes 30 s to reach the other side. She is carried 25 m downstream.
Find
\begin{enumerate}[label=(\alph*)]
\item the speed of the river, [2]
\item the speed of the swimmer relative to the water. [2]
\end{enumerate}
\hfill \mbox{\textit{Edexcel M4 2002 Q1 [4]}}