OCR MEI Further Mechanics A AS Specimen — Question 7 11 marks

Exam BoardOCR MEI
ModuleFurther Mechanics A AS (Further Mechanics A AS)
SessionSpecimen
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMomentum and Collisions
TypeCollision with coefficient of restitution
DifficultyModerate -0.3 This is a standard multi-part mechanics question testing conservation of momentum and coefficient of restitution in straightforward scenarios. Parts (i)-(iv) involve routine application of standard formulas with simple arithmetic, while part (v) tests conceptual understanding. The calculations are direct with no novel problem-solving required, making it slightly easier than average.
Spec6.03b Conservation of momentum: 1D two particles6.03f Impulse-momentum: relation6.03k Newton's experimental law: direct impact6.03l Newton's law: oblique impacts
7 Rose and Steve collide while sitting firmly on trays that are sliding on smooth horizontal ice. There are no external driving forces. Fig. 7 shows the masses of Rose and of Steve with their trays, their velocities just before their collision and the line of their motion and of their impact. Immediately after the collision, Rose has a velocity of \(0.28 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) in the direction of her motion before the collision. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{be1851d6-af11-40e1-8a36-5938ee7864d4-7_325_1047_587_482} \captionsetup{labelformat=empty} \caption{Fig. 7}
\end{figure}
  1. Find Steve's velocity after the collision.
  2. Find the coefficient of restitution between Rose and Steve on their trays. Shortly after the collision, Steve catches Rose's hand, pulls her towards him with a horizontal impulse of 4.48 Ns and then lets go of her hand.
  3. Calculate Rose's velocity after the pull. When they collide again they hold one another and move together with a common speed of \(V \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
  4. Calculate \(V\).
  5. Why did you need to know that there are no driving forces and that the ice is smooth? {www.ocr.org.uk}) after the live examination series. If OCR has unwittingly failed to correctly acknowledge or clear any third-party content in this assessment material, OCR will be happy to correct its mistake at the earliest possible opportunity. For queries or further information please contact the Copyright Team, First Floor, 9 Hills Road, Cambridge CB2 1GE.
    OCR is part of the }
Question 7:
AnswerMarks Guidance
7(i) In whole question take +ve →
Suppose Steve’s final speed is v m s -1
s
PCLM 56(cid:117)1.4(cid:16)64(cid:117)0.6(cid:32)56(cid:117)0.28(cid:14)64v
s
so v = 0.38
s
AnswerMarks
in Rose’s original directionM1
A1
A1
AnswerMarks
[3]3.3
m3.4
AnswerMarks
1.1n
+ve could be either way
e
Use of PCLM. Allow sign errors.
Accept implied (e.g. by a
diagram)
AnswerMarks Guidance
7(ii) 0.38(cid:16)0.28
Using NEL (cid:32)(cid:16)e
(cid:16)0.6(cid:16)1.4
AnswerMarks
so e = 0.05c
M1
A1
AnswerMarks
[2]i
3.4
AnswerMarks
1.1Must be right way up. FT. Accept
sign errors.
FT only from (i)
AnswerMarks Guidance
7(iii) e
p
Suppose R’s final speed is U →
4.48 + 56 × 0.28 = 56 U
S
AnswerMarks
so U = 0.36 m s -1M1
A1
AnswerMarks
[2]3.4
1.1Use of PCLM
cao Direction stated or clear
(e.g. from a diagram)
AnswerMarks Guidance
orm
Use momentums after 1st collision or after hand pullingUse momentums after 1st collision or after hand pulling M1
attempted Steve’s speed (0.31)
AnswerMarks
(56 + 64)V = 56 × 0.28 + 64 × 0.38 or (56 + 64)V = 56c
A1Either form. Allow only sign
× 0.36 + 64 × 0.31errors.
1
so V (cid:32)
AnswerMarks Guidance
3e A1
p[3]
7(v) S
So that linear momentum is conserved (after the first
AnswerMarks Guidance
collision)B1
[1]3.5b
QuestionAO1 AO2 
Question 7:
7 | (i) | In whole question take +ve →
Suppose Steve’s final speed is v m s -1
s
PCLM 56(cid:117)1.4(cid:16)64(cid:117)0.6(cid:32)56(cid:117)0.28(cid:14)64v
s
so v = 0.38
s
in Rose’s original direction | M1
A1
A1
[3] | 3.3
m3.4
1.1 | n
+ve could be either way
e
Use of PCLM. Allow sign errors.
Accept implied (e.g. by a
diagram)
7 | (ii) | 0.38(cid:16)0.28
Using NEL (cid:32)(cid:16)e
(cid:16)0.6(cid:16)1.4
so e = 0.05 | c
M1
A1
[2] | i
3.4
1.1 | Must be right way up. FT. Accept
sign errors.
FT only from (i)
7 | (iii) | e
p
Suppose R’s final speed is U →
4.48 + 56 × 0.28 = 56 U
S
so U = 0.36 m s -1 | M1
A1
[2] | 3.4
1.1 | Use of PCLM
cao Direction stated or clear
(e.g. from a diagram)
or | m
Use momentums after 1st collision or after hand pulling | Use momentums after 1st collision or after hand pulling | M1 | M1 | i | If after hand pulling, must have
attempted Steve’s speed (0.31)
(56 + 64)V = 56 × 0.28 + 64 × 0.38 or (56 + 64)V = 56 | c
A1 | Either form. Allow only sign
× 0.36 + 64 × 0.31 | errors.
1
so V (cid:32)
3 | e | A1 | cao | cao
p | [3]
7 | (v) | S
So that linear momentum is conserved (after the first
collision) | B1
[1] | 3.5b
Question | AO1 | AO2 | AO3(PS) | AO3(M) | Total
7 Rose and Steve collide while sitting firmly on trays that are sliding on smooth horizontal ice. There are no external driving forces. Fig. 7 shows the masses of Rose and of Steve with their trays, their velocities just before their collision and the line of their motion and of their impact.

Immediately after the collision, Rose has a velocity of $0.28 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ in the direction of her motion before the collision.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{be1851d6-af11-40e1-8a36-5938ee7864d4-7_325_1047_587_482}
\captionsetup{labelformat=empty}
\caption{Fig. 7}
\end{center}
\end{figure}

(i) Find Steve's velocity after the collision.\\
(ii) Find the coefficient of restitution between Rose and Steve on their trays.

Shortly after the collision, Steve catches Rose's hand, pulls her towards him with a horizontal impulse of 4.48 Ns and then lets go of her hand.\\
(iii) Calculate Rose's velocity after the pull.

When they collide again they hold one another and move together with a common speed of $V \mathrm {~m} \mathrm {~s} ^ { - 1 }$.\\
(iv) Calculate $V$.\\
(v) Why did you need to know that there are no driving forces and that the ice is smooth?

{www.ocr.org.uk}) after the live examination series.

If OCR has unwittingly failed to correctly acknowledge or clear any third-party content in this assessment material, OCR will be happy to correct its mistake at the earliest possible opportunity.

For queries or further information please contact the Copyright Team, First Floor, 9 Hills Road, Cambridge CB2 1GE.\\
OCR is part of the 
}

\hfill \mbox{\textit{OCR MEI Further Mechanics A AS  Q7 [11]}}
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