Edexcel M1 2010 January — Question 1 6 marks

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
Year2010
SessionJanuary
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMomentum and Collisions
TypeDirect collision, find impulse magnitude
DifficultyModerate -0.8 This is a straightforward M1 momentum/impulse question requiring direct application of standard formulas. Part (a) uses impulse = change in momentum with given values, and part (b) applies conservation of momentum with one unknown. Both are routine textbook exercises with no problem-solving insight required, making it easier than average.
Spec6.03b Conservation of momentum: 1D two particles6.03e Impulse: by a force6.03f Impulse-momentum: relation

A particle \(A\) of mass 2 kg is moving along a straight horizontal line with speed 12 m s\(^{-1}\). Another particle \(B\) of mass \(m\) kg is moving along the same straight line, in the opposite direction to \(A\), with speed 8 m s\(^{-1}\). The particles collide. The direction of motion of \(A\) is unchanged by the collision. Immediately after the collision, \(A\) is moving with speed 3 m s\(^{-1}\) and \(B\) is moving with speed 4 m s\(^{-1}\). Find
  1. the magnitude of the impulse exerted by \(B\) on \(A\) in the collision, [2]
  2. the value of \(m\). [4]

AnswerMarks Guidance
\(I = 2 \times 12 - 2 \times 3 = 18\) (N s)M1 A1 (2)
Part (b):
LM: \(2 \times 12 - 8m = 2 \times 3 + 4m\)
AnswerMarks Guidance
Solving to \(m = 1.5\)M1 A1 DM1 A1 (4) [6]
Alternative to (b):
\(I = m(4-(-8)) = 18\)
AnswerMarks Guidance
Solving to \(m = 1.5\)M1 A1 DM1 A1 (4)
$I = 2 \times 12 - 2 \times 3 = 18$ (N s) | M1 A1 | (2)

**Part (b):**
LM: $2 \times 12 - 8m = 2 \times 3 + 4m$
Solving to $m = 1.5$ | M1 A1 DM1 A1 | (4) [6]

**Alternative to (b):**
$I = m(4-(-8)) = 18$
Solving to $m = 1.5$ | M1 A1 DM1 A1 | (4)
A particle $A$ of mass 2 kg is moving along a straight horizontal line with speed 12 m s$^{-1}$. Another particle $B$ of mass $m$ kg is moving along the same straight line, in the opposite direction to $A$, with speed 8 m s$^{-1}$. The particles collide. The direction of motion of $A$ is unchanged by the collision. Immediately after the collision, $A$ is moving with speed 3 m s$^{-1}$ and $B$ is moving with speed 4 m s$^{-1}$. Find

\begin{enumerate}[label=(\alph*)]
\item the magnitude of the impulse exerted by $B$ on $A$ in the collision, [2]
\item the value of $m$. [4]
\end{enumerate}

\hfill \mbox{\textit{Edexcel M1 2010 Q1 [6]}}