OCR MEI AS Paper 1 (AS Paper 1) 2020 November

Question 1
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1 Celia states that \(n ^ { 2 } + 2 n + 10\) is always odd when \(n\) is a prime number. Prove that Celia’s statement is false.
Question 2
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2 Fig. 2 shows a quadrilateral ABCD . The lengths AB and BC are 5 cm and 6 cm respectively. The angles \(\mathrm { ABC } , \mathrm { ACD }\) and DAC are \(60 ^ { \circ } , 60 ^ { \circ }\) and \(75 ^ { \circ }\) respectively. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{a1b6c827-7d74-4527-9b60-58872e3d5ef7-3_547_643_740_242} \captionsetup{labelformat=empty} \caption{Fig. 2}
\end{figure} Calculate the exact value of the length AD.
Question 3
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3 Fig. 3 shows a triangle PQR . The vector \(\overrightarrow { \mathrm { PQ } }\) is \(\mathbf { i } + 7 \mathbf { j }\) and the vector \(\overrightarrow { \mathrm { QR } }\) is \(4 \mathbf { i } - 12 \mathbf { j }\). \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{a1b6c827-7d74-4527-9b60-58872e3d5ef7-3_412_234_1736_244} \captionsetup{labelformat=empty} \caption{Fig. 3}
\end{figure}
  1. Show that the triangle PQR is isosceles. The point P has position vector \(- 3 \mathbf { i } - \mathbf { j }\). The point S is added so that PQRS is a parallelogram.
  2. Find the position vector of S .
Question 4
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4 In this question, the \(x\) and \(y\) directions are horizontal and vertically upwards respectively.
A particle of mass 1.5 kg is in equilibrium under the action of its weight and forces \(\mathbf { F } _ { 1 } = \binom { 4 } { - 2 } \mathrm {~N}\)
and \(\mathbf { F } _ { 2 }\). and \(\mathbf { F } _ { 2 }\).
  1. Find the force \(\mathbf { F } _ { 2 }\). The force \(\mathbf { F } _ { 2 }\) is changed to \(\binom { 2 } { 20 } \mathrm {~N}\).
  2. Find the acceleration of the particle.
Question 5
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5 Fig. 5.1 shows part of the curve \(y = x ^ { \frac { 1 } { 2 } }\). P is the point \(( 1,1 )\) and \(Q\) is the point on the curve with \(x\)-coordinate \(1 + h\). \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{a1b6c827-7d74-4527-9b60-58872e3d5ef7-4_451_611_991_242} \captionsetup{labelformat=empty} \caption{Fig. 5.1}
\end{figure} Table 5.2 shows, for different values of \(h\), the coordinates of P , the coordinates of Q , the change in \(y\) from P to Q and the gradient of the chord PQ . \begin{table}[h]
\(x\) for P\(y\) for P\(h\)\(x\) for Q\(y\) for Qchange in \(y\)gradient PQ
111
110.11.11.0488090.0488090.488088
110.011.011.0049880.0049880.498756
110.0011.0011.0005000.0005000.499875
\captionsetup{labelformat=empty} \caption{Table 5.2}
\end{table}
  1. Fill in the missing values for the case \(h = 1\) in the copy of Table 5.2 in the Printed Answer Booklet. Give your answers correct to 6 decimal places where necessary.
  2. Explain how the sequence of values in the last column of Table 5.2 relates to the gradient of the curve \(y = x ^ { \frac { 1 } { 2 } }\) at the point \(P\).
  3. Use calculus to find the gradient of the curve at the point P .
Question 6
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6 In this question you must show detailed reasoning.
A particle moves in a straight line. Its velocity \(v \mathrm {~ms} ^ { - 1 }\) after \(t \mathrm {~s}\) is given by \(\mathrm { v } = \mathrm { t } ^ { 3 } - 5 \mathrm { t } ^ { 2 }\).
  1. Find the times at which the particle is stationary.
  2. Find the total distance travelled by the particle in the first 6 seconds.
Question 7
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7 In this question you must show detailed reasoning.
A curve has equation \(y = 4 x ^ { 3 } - 6 x ^ { 2 } - 9 x + 4\).
  1. Sketch the gradient function for this curve, clearly indicating the points where the gradient is zero.
  2. Find the set of values of \(x\) for which the gradient function is decreasing. Give your answer using set notation.
Question 8
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8 The point A has coordinates \(( - 1 , - 2 )\) and the point B has coordinates (7,4). The perpendicular bisector of \(A B\) intersects the line \(y + 2 x = k\) at \(P\). Determine the coordinates of P in terms of \(k\).
Question 9
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9 A car travelling in a straight line accelerates uniformly from rest to \(V \mathrm {~ms} ^ { - 1 }\) in \(T \mathrm {~s}\). It then slows down uniformly, coming to rest after a further \(2 T\) s.
  1. Sketch a velocity-time graph for the car. The acceleration in the first stage of the motion is \(2.5 \mathrm {~ms} ^ { - 2 }\) and the total distance travelled is 240 m .
  2. Calculate the values of \(V\) and \(T\).
Question 10
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10 An astronaut on the surface of the moon drops a ball from a point 2 m above the surface.
  1. Without any calculations, explain why a standard model using \(g = 9.8 \mathrm {~ms} ^ { - 2 }\) will not be appropriate to model the fall of the ball. The ball takes 1.6s to hit the surface.
  2. Find the acceleration of the ball which best models its motion. Give your answer correct to 2 significant figures.
  3. Use this value to predict the maximum height of the ball above the point of projection when thrown vertically upwards with an initial velocity of \(15 \mathrm {~ms} ^ { - 1 }\).
Question 11
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11 In this question you must show detailed reasoning.
  1. A student is asked to solve the inequality \(x ^ { \frac { 1 } { 2 } } < 4\). The student argues that \(x ^ { \frac { 1 } { 2 } } < 4 \Leftrightarrow x < 16\), so that the solution is \(\{ x : x < 16 \}\).
    Comment on the validity of the student's argument.
  2. Solve the inequality \(\left( \frac { 1 } { 2 } \right) ^ { x } < 4\).
  3. Show that the equation \(2 \log _ { 2 } ( x + 8 ) - \log _ { 2 } ( x + 6 ) = 3\) has only one root.
Question 12
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12 In this question you must show detailed reasoning. Fig. 12 shows part of the graph of \(y = x ^ { 2 } + \frac { 1 } { x ^ { 2 } }\). \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{a1b6c827-7d74-4527-9b60-58872e3d5ef7-7_574_574_402_233} \captionsetup{labelformat=empty} \caption{Fig. 12}
\end{figure} The tangent to the curve \(\mathrm { y } = \mathrm { x } ^ { 2 } + \frac { 1 } { \mathrm { x } ^ { 2 } }\) at the point \(\left( 2 , \frac { 17 } { 4 } \right)\) meets the \(x\)-axis at A and meets the \(y\)-axis at B . O is the origin.
  1. Find the exact area of the triangle OAB .
  2. Use calculus to prove that the complete curve has two minimum points and no maximum point. \section*{END OF QUESTION PAPER}