4   6 The graph shows how the potential V varies with distance d in an electric field. V d Which of the following shows the corresponding variation in electric field strength E? E d E d A B E d E d C D (Total for Question 6 = 1 mark) 7 Which of the following quantities is a vector? A charge B mass C momentum D time (Total for Question 7 = 1 mark) Turn over 5   8 A point object has a charge +Q. Which of the following diagrams shows equipotential lines differing by a constant potential difference, and electric field lines around the object? A B C D (Total for Question 8 = 1 mark) 6   Questions 9 and 10 refer to the information below. Alpha particle scattering investigations were first carried out in the early part of the 20th century. 9 An alpha particle with initial kinetic energy 8.8 × 10−13 J approaches a nucleus of a gold (197 79Au) atom. Which of the following is an equation for the closest distance r, in metres, between the alpha particle and the nucleus? A r = 8.99 × 109 2 1 6 10 79 1 6 10 8 8 10 19 19 13 × × × × × ×     − − − . . . B r = 2 1 6 10 197 1 6 10 8 99 10 8 8 10 19 19 9 13 × × × × × × × × − − − . . . . C r = 8.99 × 109 8 8 10 4 1 6 10 79 1 6 10 13 19 19 . . . × × × × × ×     − − − D r = 8.99 × 109 2 79 8 8 10 13 × ×     − . (Total for Question 9 = 1 mark) 10 Which of the following conclusions could not be made as a result of these investigations? A The atom is mostly empty space. B The atom is neutral. C The nucleus is charged. D The nucleus is very small compared to the atom. (Total for Question 10 = 1 mark) Turn over 7   11 A student drives a go‑kart up a slope. (a) The slope is at an angle of 5.7° to the horizontal. The go‑kart moves with a constant velocity of 2.8 m s−1. Calculate the power of the go‑kart. mass of go‑kart and driver = 60 kg resistive force on the go‑kart = 18 N (4) ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... Power = ....................................................... (b) The go‑kart is powered by a battery connected to a motor. The rate of thermal energy transfer by the wiring in the motor is 55 W. Calculate the resistance of the wiring in the motor. current in motor = 24 A (2) ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... Resistance of the wiring in the motor = ....................................................... (Total for Question 11 = 6 marks) 8   12 The photograph shows a cyclist cycling at a constant velocity on horizontal ground. (a) Complete the free‑body force diagram to show the four forces acting on the bicycle. Treat the bicycle and cyclist as a single object. One force has been added for you. (3) friction force on rear wheel (b) The cyclist stops pedalling and comes to rest in a time of 5.2 s. (i) Sketch a graph to show how the cyclist’s velocity changes during this time. Assume the deceleration is constant. (2) Velocity Time Turn over 9   (ii) The cyclist travels 7.80 m while coming to rest. Calculate the average resistive force on the cyclist and bicycle. mass of cyclist and bicycle = 28.0 kg (4) ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................... Average resistive force = ....................................................... (Total for Question 12 = 9 marks)