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1917 Paper 1 Q105
D: 1500.0 B: 1500.0

Taking as rectangular coordinates the kinetic energy of a particle moving in a straight line and the reciprocal of the resultant force acting on it, and drawing a curve to represent the motion, shew that the distance travelled is represented by the area under this curve. Sketch the curve for the case of a vehicle driven by an engine which is working at constant horse-power, the only resistance being a force proportional to the square of the velocity. Shew that the velocity has a certain limiting value; and calculate the distance travelled while the velocity increases from a half to three quarters of this limiting value, taking the mass of the vehicle as 2000 pounds, the horse-power as 100, and the limiting velocity as 150 feet per second.

1917 Paper 1 Q105
D: 1500.0 B: 1500.0

Prove, by use of the identity \[ \frac{1}{1+x+x^2} = \frac{1-x}{1-x^3}, \] or otherwise, that \[ 1 - (n-1) + \frac{(n-2)(n-3)}{1.2} - \frac{(n-3)(n-4)(n-5)}{1.2.3} + \dots \] (the series being continued so long as all the factors in the numerator are positive) is equal to \(-1, 0, \text{ or } 1\): and give rules for distinguishing between the different cases.

1917 Paper 1 Q105
D: 1500.0 B: 1500.0

A light string \(ABCDE\), of length 100 inches, is divided into four equal parts at \(B, C, D\). The ends \(A\) and \(E\) are fixed in the same horizontal at a distance 88 inches apart, and weights \(W, W'\) and \(W\) are hung from \(B, C\) and \(D\). If in equilibrium the depth of \(C\) below \(AE\) is 22 inches, shew that \(W:W' = 11:14\), and that the tensions in \(AB\) and \(BC\) are in the ratio 6:5.

1917 Paper 1 Q105
D: 1500.0 B: 1500.0

Find the sum of the cubes of the first \(n\) natural numbers. Find the sum to \(2n+1\) terms of the series \(1^3-2^3+3^3-4^3+\dots\).

1917 Paper 1 Q105
D: 1500.0 B: 1500.0

The equation of a rational algebraic curve of the \(n\)th degree being written in the form \[ x^n f_0\left(\frac{y}{x}\right) + x^{n-1} f_1\left(\frac{y}{x}\right) + x^{n-2} f_2\left(\frac{y}{x}\right) + \dots = 0, \] obtain the asymptotes of the curve; and find the conditions that it may have (i) an inflexional asymptote, (ii) two parallel asymptotes, (iii) a parabolic asymptote. Trace the curve \(x(y^2-4x^2)-x-2y+3=0\), and shew that \((\frac{1}{2},2)\) is a double point.

1917 Paper 1 Q106
D: 1500.0 B: 1500.0

A well-known safety device for lifts consists of an extension of the lift shaft below ground level; the floor of the lift is made to fit this well closely, so that a pneumatic buffer is provided. A lift weighing 3000 lbs. falls from a height of 30 ft. above ground level into such a safety pit 10 ft. deep, the base of the lift being 8 ft. by 5 ft. Find approximately how far the lift will descend before it is stopped, neglecting air leakage and assuming that the pressure of the air varies inversely as its volume. The resulting equation may be solved graphically: take atmospheric pressure as 15 lbs. per sq. in.

1917 Paper 1 Q106
D: 1500.0 B: 1500.0

Prove that \[ \begin{vmatrix} 1 & 1 & 1 \\ \sec A & \sec B & \sec C \\ \cosec A & \cosec B & \cosec C \end{vmatrix} = 16 \frac{\sin\frac{B-C}{2} \sin\frac{C-A}{2} \sin\frac{A-B}{2}}{\sin 2A \sin 2B \sin 2C} \{\sin(B+C) + \sin(C+A) + \sin(A+B)\}. \]

1917 Paper 1 Q106
D: 1500.0 B: 1500.0

A tripod, formed of three equal rods each of weight \(2W\) smoothly hinged together at one end, stands on a smooth horizontal plane, and a weight \(W\) is suspended from the hinge. Equilibrium is maintained by light strings joining the feet \(A, B, C\) of the rods. Shew that the pressure on the plane at \(A\) is \(W(3-2\cot B \cot C)\), and that the tensions of the strings are given by \(T_1 \cos A = T_2 \cos B = T_3 \cos C = 2W \tan\theta \cot A \cot B \cot C\), where \(\theta\) is the inclination of each rod to the vertical.

1917 Paper 1 Q106
D: 1500.0 B: 1500.0

Find correct to two decimal places the real root of the equation \[ x^3+x^2+x-100=0. \]

1917 Paper 1 Q106
D: 1500.0 B: 1500.0

Write an essay on the determination of the state of stress in a plane frame built up by light rigid bars, which are smoothly jointed. Consider (i) the relation between the number of joints and the number of bars in a frame, which is just stiff,

  1. [(ii)] the theorem that when such a frame is acted on by a system of equilibrating coplanar forces at the joints, the stresses are determinate,
  2. [(iii)] Bow's notation and reciprocal diagrams.
A jointed framework is formed of six equal light bars forming an open hexagon \(ABCDEFG\) inscribed in a semicircle, \(AG\) being the diameter, which is horizontal (so that \(D\) is vertically above the centre), and of the seven radii to the vertices. The frame is attached to a fixed point at \(A\) and supported at \(G\); equal and opposite horizontal forces act at \(B\) and \(D\). Determine the stresses.