OCR MEI Further Mechanics B AS 2022 June — Question 1 9 marks

Exam BoardOCR MEI
ModuleFurther Mechanics B AS (Further Mechanics B AS)
Year2022
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCircular Motion 1
TypeRadial and transverse acceleration
DifficultyStandard +0.3 This is a straightforward circular motion question requiring standard techniques: converting linear to angular speed (v=rω), integrating to find distance, and applying F=mv²/r for the normal force. Part (c) involves solving a quadratic equation but all steps are routine applications of formulas with no novel problem-solving required. Slightly above average due to the multi-part nature and algebraic manipulation needed.
Spec3.03b Newton's first law: equilibrium3.03c Newton's second law: F=ma one dimension6.05a Angular velocity: definitions6.05b Circular motion: v=r*omega and a=v^2/r

1 A small smooth ring of mass 0.5 kg is travelling round a smooth circular wire, with centre O and radius 0.8 m . The circle of wire is in a horizontal plane. The speed of the ring, \(v \mathrm {~ms} ^ { - 1 }\), at time \(t \mathrm {~s}\) after passing through a point A on the wire is given by \(\mathrm { v } = 0.2 \mathrm { t } ^ { 2 } + 0.4 \mathrm { t } + 0.1\).
  1. Find the angular speed of the ring 5 seconds after it passes through A .
  2. Find the distance the ring travels along the wire in the first second after passing through A . At time \(T\) s after the ring passes through A the magnitude of the force exerted on the ring by the wire is 6.4 N . You may assume that any forces acting on the ring other than the force exerted on the ring by the wire and gravity can be ignored.
    1. Determine the value of \(T\).
    2. Hence find the tangential acceleration of the ring at this time.

Question 1:
AnswerMarks Guidance
1(a) 0.2 0.4 0.1
πœ” = 𝑑2 + 𝑑+
AnswerMarks Guidance
0.8 0.8 0.8M1 1.2
0.1(=7.1)
AnswerMarks Guidance
πœ”(5) = 8.875 (rad sβˆ’1)A1 1.1
[2]
AnswerMarks
(b)0.2 0.4
𝑠 = 𝑑3 + 𝑑2 +0.1𝑑 (+𝑐)
AnswerMarks Guidance
3 2M1 1.1a
correct
AnswerMarks Guidance
Dist = 0.367 (m)A1 1.1
1
∫ 0.2𝑑2 +0.4𝑑+0.1d𝑑
0
= 0.367
[2]
(c)
AnswerMarks
(i)0.5𝑣2
6.4 =
AnswerMarks Guidance
0.8M1 3.1b
v = 3.2 (m sβˆ’1)Or Ο‰ = 4
3.2 = 0.2𝑑2+0.4𝑑+0.1 and attempt to solveM1 1.1
implied by correct answer
1
T = 3.06 orβˆ’1+ √66 (s)
AnswerMarks Guidance
2A1 1.1
Accept 3.1BC – don’t need to see the
method used to find root(s).
[3]
AnswerMarks Guidance
(ii)π‘Ž = 0.4𝑑+0.4 M1
Tang acc = 1.62 (m sβˆ’2)A1 1.1
[1.6, 1.65]Allow 2.0(31) rad sβˆ’2
[2]
Question 1:
1 | (a) | 0.2 0.4 0.1
πœ” = 𝑑2 + 𝑑+
0.8 0.8 0.8 | M1 | 1.2 | Or 𝑣(5) = 0.2Γ—52 +0.4Γ—5+
0.1(=7.1)
πœ”(5) = 8.875 (rad sβˆ’1) | A1 | 1.1 | Accept 8.9
[2]
(b) | 0.2 0.4
𝑠 = 𝑑3 + 𝑑2 +0.1𝑑 (+𝑐)
3 2 | M1 | 1.1a | All powers and at least one coeff
correct
Dist = 0.367 (m) | A1 | 1.1 | 0.366666… Accept 0.37 | BC allow
1
∫ 0.2𝑑2 +0.4𝑑+0.1d𝑑
0
= 0.367
[2]
(c)
(i) | 0.5𝑣2
6.4 =
0.8 | M1 | 3.1b | OR 6.4 = 0.5Γ—0.8Γ—πœ”2
v = 3.2 (m sβˆ’1) | Or Ο‰ = 4
3.2 = 0.2𝑑2+0.4𝑑+0.1 and attempt to solve | M1 | 1.1 | Or 4= 0.25𝑑2+0.5𝑑+0.125 | Attempt to solve can be
implied by correct answer
1
T = 3.06 orβˆ’1+ √66 (s)
2 | A1 | 1.1 | 3.062019… Not βˆ’5.06
Accept 3.1 | BC – don’t need to see the
method used to find root(s).
[3]
(ii) | π‘Ž = 0.4𝑑+0.4 | M1 | 3.1b | Or πœ”Μ‡ = 0.5𝑑+0.5
Tang acc = 1.62 (m sβˆ’2) | A1 | 1.1 | 1.6248… Accept answers in range
[1.6, 1.65] | Allow 2.0(31) rad sβˆ’2
[2]
1 A small smooth ring of mass 0.5 kg is travelling round a smooth circular wire, with centre O and radius 0.8 m . The circle of wire is in a horizontal plane.

The speed of the ring, $v \mathrm {~ms} ^ { - 1 }$, at time $t \mathrm {~s}$ after passing through a point A on the wire is given by $\mathrm { v } = 0.2 \mathrm { t } ^ { 2 } + 0.4 \mathrm { t } + 0.1$.
\begin{enumerate}[label=(\alph*)]
\item Find the angular speed of the ring 5 seconds after it passes through A .
\item Find the distance the ring travels along the wire in the first second after passing through A .

At time $T$ s after the ring passes through A the magnitude of the force exerted on the ring by the wire is 6.4 N . You may assume that any forces acting on the ring other than the force exerted on the ring by the wire and gravity can be ignored.
\item \begin{enumerate}[label=(\roman*)]
\item Determine the value of $T$.
\item Hence find the tangential acceleration of the ring at this time.
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{OCR MEI Further Mechanics B AS 2022 Q1 [9]}}