CAIE M1 2003 November — Question 4 6 marks

Exam BoardCAIE
ModuleM1 (Mechanics 1)
Year2003
SessionNovember
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicWork done and energy
TypeParticle on smooth curved surface
DifficultyModerate -0.8 This is a straightforward application of conservation of energy and work-energy principles with standard values. Part (i) uses PE = KE directly, part (ii) adds a simple work-done-against-resistance calculation. Both are routine M1 mechanics exercises requiring only direct substitution into familiar formulas with no problem-solving insight needed.
Spec6.02c Work by variable force: using integration6.02e Calculate KE and PE: using formulae

4 \includegraphics[max width=\textwidth, alt={}, center]{5cba3e17-3979-4c22-a415-2cdd60f09289-2_227_586_1631_781} The diagram shows a vertical cross-section of a surface. \(A\) and \(B\) are two points on the cross-section. A particle of mass 0.15 kg is released from rest at \(A\).
  1. Assuming that the particle reaches \(B\) with a speed of \(8 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and that there are no resistances to motion, find the height of \(A\) above \(B\).
  2. Assuming instead that the particle reaches \(B\) with a speed of \(6 \mathrm {~ms} ^ { - 1 }\) and that the height of \(A\) above \(B\) is 4 m , find the work done against the resistances to motion.

AnswerMarks Guidance
KE (gain) = \(\frac{1}{2} \times 0.15 \times 8^2\)B1
For using PE loss = KE gainM1
Height is 3.2 mA1 3 marks
For using WD is difference in PE loss and KE gainM1
\(WD = 0.15 \times 10 \times 4 - \frac{1}{2} \times 0.15 \times 6^2\)A1
Work Done is 3.3 JA1 3 marks
SR: For candidates who treat AB as if it is straight and vertical (implicitly or otherwise)Max 2 out of 6 marks
(i) \(a = 8^2 \div (2 \times 10) = 3.2\)B1
(ii) \(a = 6^2 + (2 \times 4) = 4.5\) and \(R = 0.15 \times 10 - 0.15 \times 4.5 = 0.825\) and \(WD = 4 \times 0.825 = 3.3\)B1 2 marks
KE (gain) = $\frac{1}{2} \times 0.15 \times 8^2$ | B1 |

For using PE loss = KE gain | M1 |
Height is 3.2 m | A1 | 3 marks

For using WD is difference in PE loss and KE gain | M1 |
$WD = 0.15 \times 10 \times 4 - \frac{1}{2} \times 0.15 \times 6^2$ | A1 |
Work Done is 3.3 J | A1 | 3 marks

**SR:** For candidates who treat AB as if it is straight and vertical (implicitly or otherwise) | Max 2 out of 6 marks
(i) $a = 8^2 \div (2 \times 10) = 3.2$ | B1
(ii) $a = 6^2 + (2 \times 4) = 4.5$ and $R = 0.15 \times 10 - 0.15 \times 4.5 = 0.825$ and $WD = 4 \times 0.825 = 3.3$ | B1 | 2 marks

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\includegraphics[max width=\textwidth, alt={}, center]{5cba3e17-3979-4c22-a415-2cdd60f09289-2_227_586_1631_781}

The diagram shows a vertical cross-section of a surface. $A$ and $B$ are two points on the cross-section. A particle of mass 0.15 kg is released from rest at $A$.\\
(i) Assuming that the particle reaches $B$ with a speed of $8 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ and that there are no resistances to motion, find the height of $A$ above $B$.\\
(ii) Assuming instead that the particle reaches $B$ with a speed of $6 \mathrm {~ms} ^ { - 1 }$ and that the height of $A$ above $B$ is 4 m , find the work done against the resistances to motion.

\hfill \mbox{\textit{CAIE M1 2003 Q4 [6]}}