OCR MEI Further Mechanics Major 2019 June — Question 3 5 marks

Exam BoardOCR MEI
ModuleFurther Mechanics Major (Further Mechanics Major)
Year2019
SessionJune
Marks5
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Mark schemeDownload PDF ↗
TopicImpulse and momentum (advanced)
TypeVelocity after impulse (direct calculation)
DifficultyModerate -0.3 This is a straightforward impulse-momentum question requiring application of the impulse-momentum theorem (Δp = J) to find final velocity, then calculating speed from velocity components. The vector arithmetic is routine and the modelling assumption is standard recall. Slightly easier than average due to being a direct application with no problem-solving insight needed, though the vector notation and multi-step calculation keep it close to typical A-level standard.
Spec6.03f Impulse-momentum: relation6.03g Impulse in 2D: vector form
A ball of mass \(2\)kg is moving with velocity \((3\mathbf{i} - 2\mathbf{j})\)ms\(^{-1}\) when it is struck by a bat. The impulse on the ball is \((-8\mathbf{i} + 10\mathbf{j})\)Ns.
  1. Find the speed of the ball immediately after the impact. [4]
  2. State one modelling assumption you have used in answering part (a). [1]
Question 3:
AnswerMarks Guidance
3(a) 8i10j2  v 3i2j 
vi3j
 v  12 32
AnswerMarks
v  10M1*
A1
M1dep*
A1
AnswerMarks
[4]3.3
1.1
1.1
AnswerMarks
1.1Use of impulse = change of
momentum – must be using m = 2
oe (e.g. as a column vector)
2
Correct method for either v or v
from their v
AnswerMarks
oe (awrt 3 sf)Must be using
subtraction
3.162277…
AnswerMarks Guidance
3(b) The ball is modelled as a particle
[1]3.5b The impact of the ball and bat is
instantaneous
Question 3:
3 | (a) | 8i10j2  v 3i2j 
vi3j
 v  12 32
v  10 | M1*
A1
M1dep*
A1
[4] | 3.3
1.1
1.1
1.1 | Use of impulse = change of
momentum – must be using m = 2
oe (e.g. as a column vector)
2
Correct method for either v or v
from their v
oe (awrt 3 sf) | Must be using
subtraction
3.162277…
3 | (b) | The ball is modelled as a particle | B1
[1] | 3.5b | The impact of the ball and bat is
instantaneous
A ball of mass $2$kg is moving with velocity $(3\mathbf{i} - 2\mathbf{j})$ms$^{-1}$ when it is struck by a bat. The impulse on the ball is $(-8\mathbf{i} + 10\mathbf{j})$Ns.

\begin{enumerate}[label=(\alph*)]
\item Find the speed of the ball immediately after the impact. [4]
\item State one modelling assumption you have used in answering part (a). [1]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI Further Mechanics Major 2019 Q3 [5]}}
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