| Exam Board | OCR |
|---|---|
| Module | M1 (Mechanics 1) |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Momentum and Collisions |
| Type | Collision with friction after impact |
| Difficulty | Standard +0.3 This is a standard M1 collision problem requiring conservation of momentum (part i) followed by basic kinematics (part ii). The setup is straightforward with clear given values, and both parts use routine techniques without requiring problem-solving insight or handling of edge cases. Slightly above average difficulty only due to the two-part structure and need to track directions carefully. |
| Spec | 3.02d Constant acceleration: SUVAT formulae6.03b Conservation of momentum: 1D two particles |
Two small spheres $P$ and $Q$ have masses $0.1$ kg and $0.2$ kg respectively. The spheres are moving directly towards each other on a horizontal plane and collide. Immediately before the collision $P$ has speed $4$ m s$^{-1}$ and $Q$ has speed $3$ m s$^{-1}$. Immediately after the collision the spheres move away from each other, $P$ with speed $u$ m s$^{-1}$ and $Q$ with speed $(3.5 - u)$ m s$^{-1}$.
\begin{enumerate}[label=(\roman*)]
\item Find the value of $u$. [4]
\end{enumerate}
After the collision the spheres both move with deceleration of magnitude $5$ m s$^{-2}$ until they come to rest on the plane.
\begin{enumerate}[label=(\roman*)]
\setcounter{enumi}{1}
\item Find the distance $PQ$ when both $P$ and $Q$ are at rest. [4]
\end{enumerate}
\hfill \mbox{\textit{OCR M1 Q3 [8]}}