CAIE M1 2012 November — Question 5 8 marks

Exam BoardCAIE
ModuleM1 (Mechanics 1)
Year2012
SessionNovember
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicConstant acceleration (SUVAT)
TypeDisplacement expressions and comparison
DifficultyModerate -0.3 This is a straightforward two-part SUVAT question requiring standard application of kinematic equations (v = u + at, v² = u² + 2as) in part (i), and basic integration of a velocity function in part (ii). All steps are routine with no problem-solving insight needed, making it slightly easier than average.
Spec3.02d Constant acceleration: SUVAT formulae3.02f Non-uniform acceleration: using differentiation and integration

5 Particle \(P\) travels along a straight line from \(A\) to \(B\) with constant acceleration \(0.05 \mathrm {~m} \mathrm {~s} ^ { - 2 }\). Its speed at \(A\) is \(2 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and its speed at \(B\) is \(5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
  1. Find the time taken for \(P\) to travel from \(A\) to \(B\), and find also the distance \(A B\). Particle \(Q\) also travels along the same straight line from \(A\) to \(B\), starting from rest at \(A\). At time \(t \mathrm {~s}\) after leaving \(A\), the speed of \(Q\) is \(k t ^ { 3 } \mathrm {~m} \mathrm {~s} ^ { - 1 }\), where \(k\) is a constant. \(Q\) takes the same time to travel from \(A\) to \(B\) as \(P\) does.
  2. Find the value of \(k\) and find \(Q\) 's speed at \(B\).

(i)
AnswerMarks Guidance
\([5 = 2 + 0.05t\) or \(25 = 4 + 2 \times 0.05(AB)]\)M1 For using \(v = u + at\) or \(v^2 = u^2 + 2as\)
Time taken is 60 s (or Distance is 210 m)A1
Distance is 210 m (or Time taken is 60 s)B1 3
(ii)
AnswerMarks Guidance
\(s = kt^4 (+C)\)B1
\(C = 0\) (may be implied by its absence)B1
\([210 = k \times 60^3/4]\)M1 For using \(s = 210\) when \(t = 60\)
\(k = 7/1080000\) or 0.0000648A1
Speed of Q at B is 14 ms\(^{-1}\)B1 ft 5
**(i)**
$[5 = 2 + 0.05t$ or $25 = 4 + 2 \times 0.05(AB)]$ | M1 | For using $v = u + at$ or $v^2 = u^2 + 2as$
Time taken is 60 s (or Distance is 210 m) | A1 |
Distance is 210 m (or Time taken is 60 s) | B1 | 3

**(ii)**
$s = kt^4 (+C)$ | B1 |
$C = 0$ (may be implied by its absence) | B1 |
$[210 = k \times 60^3/4]$ | M1 | For using $s = 210$ when $t = 60$
$k = 7/1080000$ or 0.0000648 | A1 |
Speed of Q at B is 14 ms$^{-1}$ | B1 ft | 5 | If $k \times 60^3$
5 Particle $P$ travels along a straight line from $A$ to $B$ with constant acceleration $0.05 \mathrm {~m} \mathrm {~s} ^ { - 2 }$. Its speed at $A$ is $2 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ and its speed at $B$ is $5 \mathrm {~m} \mathrm {~s} ^ { - 1 }$.\\
(i) Find the time taken for $P$ to travel from $A$ to $B$, and find also the distance $A B$.

Particle $Q$ also travels along the same straight line from $A$ to $B$, starting from rest at $A$. At time $t \mathrm {~s}$ after leaving $A$, the speed of $Q$ is $k t ^ { 3 } \mathrm {~m} \mathrm {~s} ^ { - 1 }$, where $k$ is a constant. $Q$ takes the same time to travel from $A$ to $B$ as $P$ does.\\
(ii) Find the value of $k$ and find $Q$ 's speed at $B$.

\hfill \mbox{\textit{CAIE M1 2012 Q5 [8]}}