Edexcel M1 2002 November — Question 6 11 marks

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
Year2002
SessionNovember
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMomentum and Collisions
TypeCollision with friction after impact
DifficultyModerate -0.8 This is a straightforward M1 collision problem requiring only standard application of conservation of momentum (part a is a 'show that'), followed by basic equations of motion with constant force/deceleration. All three parts use routine textbook methods with no problem-solving insight required, making it easier than average but not trivial due to the multi-part structure and numerical work involved.
Spec6.03a Linear momentum: p = mv6.03b Conservation of momentum: 1D two particles6.03i Coefficient of restitution: e6.03j Perfectly elastic/inelastic: collisions6.03k Newton's experimental law: direct impact6.03l Newton's law: oblique impacts

6. A railway truck \(P\) of mass 1500 kg is moving on a straight horizontal track. The truck \(P\) collides with a truck \(Q\) of 2500 kg at a point \(A\). Immediately before the collision, \(P\) and \(Q\) are moving in the same direction with speeds \(10 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and \(5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) respectively. Immediately after the collision, the direction of motion of \(P\) is unchanged and its speed is \(4 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). By modelling the trucks as particles,
  1. show that the speed of \(Q\) immediately after the collision is \(8.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). After the collision at \(A\), the truck \(P\) is acted upon by a constant braking force of magnitude 500 N . The truck \(P\) comes to rest at the point \(B\).
  2. Find the distance \(A B\). After the collision \(Q\) continues to move with constant speed \(8.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
  3. Find the distance between \(P\) and \(Q\) at the instant when \(P\) comes to rest.

Question 6:
Part (a):
AnswerMarks Guidance
Answer/WorkingMarks Notes
\(1500 \times 10 + 2500 \times 5 = 1500 \times 4 + 2500 \times v\)M1 A1
\(v = 8.6 \text{ m s}^{-1}\)A1 (3)
Part (b):
AnswerMarks Guidance
Answer/WorkingMarks Notes
\(P: 1500a = -500 \Rightarrow a = -\frac{1}{3} \text{ m s}^{-2}\)M1
\(0^2 = 4^2 - 2 \times \frac{1}{3} \times s \Rightarrow s = 24\) mM1 A1 (3)
Part (c):
AnswerMarks Guidance
Answer/WorkingMarks Notes
\(P: 0 = 4 - \frac{1}{3}t \Rightarrow t = 12\) sM1
\(Q: s = 8.6 \times 12 = 103.2\) mM1 A1
Distance apart \(= 103.2 - 24 = 79.2\) mM1 A1 (5)
## Question 6:

### Part (a):
| Answer/Working | Marks | Notes |
|---|---|---|
| $1500 \times 10 + 2500 \times 5 = 1500 \times 4 + 2500 \times v$ | M1 A1 | |
| $v = 8.6 \text{ m s}^{-1}$ | A1 | **(3)** |

### Part (b):
| Answer/Working | Marks | Notes |
|---|---|---|
| $P: 1500a = -500 \Rightarrow a = -\frac{1}{3} \text{ m s}^{-2}$ | M1 | |
| $0^2 = 4^2 - 2 \times \frac{1}{3} \times s \Rightarrow s = 24$ m | M1 A1 | **(3)** |

### Part (c):
| Answer/Working | Marks | Notes |
|---|---|---|
| $P: 0 = 4 - \frac{1}{3}t \Rightarrow t = 12$ s | M1 | |
| $Q: s = 8.6 \times 12 = 103.2$ m | M1 A1 | |
| Distance apart $= 103.2 - 24 = 79.2$ m | M1 A1 | **(5)** |

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6. A railway truck $P$ of mass 1500 kg is moving on a straight horizontal track. The truck $P$ collides with a truck $Q$ of 2500 kg at a point $A$. Immediately before the collision, $P$ and $Q$ are moving in the same direction with speeds $10 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ and $5 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ respectively. Immediately after the collision, the direction of motion of $P$ is unchanged and its speed is $4 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. By modelling the trucks as particles,
\begin{enumerate}[label=(\alph*)]
\item show that the speed of $Q$ immediately after the collision is $8.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }$.

After the collision at $A$, the truck $P$ is acted upon by a constant braking force of magnitude 500 N . The truck $P$ comes to rest at the point $B$.
\item Find the distance $A B$.

After the collision $Q$ continues to move with constant speed $8.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }$.
\item Find the distance between $P$ and $Q$ at the instant when $P$ comes to rest.
\end{enumerate}

\hfill \mbox{\textit{Edexcel M1 2002 Q6 [11]}}