| Exam Board | Edexcel |
|---|---|
| Module | M4 (Mechanics 4) |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Oblique and successive collisions |
| Type | Sphere rebounds off fixed wall obliquely |
| Difficulty | Standard +0.3 This is a standard M4 oblique collision problem requiring decomposition of velocity into components parallel and perpendicular to the wall, application of the coefficient of restitution formula to the perpendicular component, and recombination using Pythagoras. It's slightly easier than average as it follows a well-practiced procedure with straightforward arithmetic (30° angle gives clean values), though it does require understanding of the oblique collision model. |
| Spec | 6.03j Perfectly elastic/inelastic: collisions6.03k Newton's experimental law: direct impact |
\begin{enumerate}
\item A smooth sphere $S$ is moving on a smooth horizontal plane with speed $u$ when it collides with a smooth fixed vertical wall. At the instant of collision the direction of motion of $S$ makes an angle of $30 ^ { \circ }$ with the wall. The coefficient of restitution between $S$ and the wall is $\frac { 1 } { 3 }$.
\end{enumerate}
Find the speed of $S$ immediately after the collision.\\
\hfill \mbox{\textit{Edexcel M4 Q1 [6]}}