| Exam Board | Edexcel |
|---|---|
| Module | M2 (Mechanics 2) |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Momentum and Collisions |
| Type | Collision with vector velocities |
| Difficulty | Moderate -0.3 This is a straightforward application of conservation of momentum in vector form. Students need to set up the momentum equation with masses m and 2m, substitute the given velocities, and solve for the unknown velocity vector. It requires only direct application of a standard formula with no conceptual challenges or problem-solving insight, making it slightly easier than average. |
| Spec | 6.03b Conservation of momentum: 1D two particles |
| Answer | Marks | Guidance |
|---|---|---|
| \(m(5i + 6j) + 2mu = m(-3i + 2j) + 2m(i - 3j)\) | M1 A1 | |
| \(5i + 6j + 2u = -i - 4j\) | ||
| \(2u = -6i - 10j\) | ||
| \(u = (-3i - 5j) \text{ ms}^{-1}\) | M1 A1 A1 | 5 marks |
$m(5i + 6j) + 2mu = m(-3i + 2j) + 2m(i - 3j)$ | M1 A1 |
$5i + 6j + 2u = -i - 4j$ | |
$2u = -6i - 10j$ | |
$u = (-3i - 5j) \text{ ms}^{-1}$ | M1 A1 A1 | 5 marks\begin{enumerate}
\item A snooker ball $A$ is moving on a horizontal table with velocity $( 5 \mathbf { i } + 6 \mathbf { j } ) \mathrm { ms } ^ { - 1 }$.
\end{enumerate}
It collides with another ball $B$, whose mass is twice the mass of $A$.\\
After the collision, $A$ has velocity $( - 3 \mathbf { i } + 2 \mathbf { j } ) \mathrm { ms } ^ { - 1 }$ and $B$ has velocity $( \mathbf { i } - 3 \mathbf { j } ) \mathrm { ms } ^ { - 1 }$.\\
Find the velocity of $B$ before the collision.\\
\hfill \mbox{\textit{Edexcel M2 Q1 [5]}}