GYSS 4E Prelim Physics P2 Question

2 Section A (70 marks) Answer all the questions in the spaces provided. 1 The diagram shows a model car with a mass of 0.25 kg. The car is travelling at a constant speed of 1.70 m/s as it approaches the rough ramp. The average friction opposing the motion of the car down the ramp is 0.15 N. Assume air resistance is negligible. (a) Calculate the work done against friction as it moves down the rough ramp. work done against friction = ………………………… [1] (b) Calculate (i) the loss in gravitational potential energy as the car moves down the ramp, loss of gravitational potential energy = ………………………… [1] (ii) the speed of the car at the bottom of the rough ramp. speed of the car = ……………………………… [2] 0.80 m 0.42 m

3 (c) Draw a free body diagram of the car moving down the ramp, labelling the forces acting on the car. [2] [Total: 6] 2 Fig. 2.1 shows a lorry accelerating along a straight road. The driving force exerted on the lorry in the forward direction is D and the total backward force acting on the lorry is B. Fig. 2.1 The gravitational field strength is 10 N/kg. (a) Compare the magnitude of the forces D and B. Give a reason for your answer. ……………………………………………………………………………………………… ……………………………………………………………………………………...……[1] (b) The lorry subsequently turns a corner at a constant speed of 12 m/s. (i) Express the speed of the lorry in km/h. speed = …………………………[1]

4 (ii) State and explain whether the lorry is accelerating when it turns the corner. ……………………………………………………………………………… …………………………………………………………………...………[1] [Total: 3] 3 Fig. 3.1 shows a uniform plank of mass 5.0 kg and length 2.0 m resting horizontally on two trestles, P and Q. Fig. 3.1 Trestle Q exerts a force of 440 N on the plank when an object of mass 65.0 kg is placed at a distance, d, from P. The gravitational field strength, g = 10 N/kg. (a) Calculate the moment due to the weight of the plank. moment due to weight of plank = ……………………………..[1] (b) Define principle of moment. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………...……[1] P Q d 65 kg

5 (c) Determine the distance d, of the object from P. d = …………………………….[2] [Total: 4] 4 (a) Fig. 4.1 shows a ray of light XY being directed at the surface AB of an irregular- shaped glass block ABCDE. Fig. 4.1 (i) Explain why the ray XY enters surface AB without bending. …………………………………………………………………………………..[1] (ii) Determine the critical angle of the glass. critical angle = .................................................. [1] D A B C E X Y 46 110

6 (iii) Calculate the speed of the light ray in the glass block. speed = …………………………………….. [2] (b) Fig. 4.2 shows how a thin converging lens L made of the same glass is used to produce a sharp image of an arrow that is twice the size of the illuminated object. In the space below, complete a scale diagram of two rays from the top of the object to show how the sharp image in Fig. 4.2 is formed. Fig. 4.2 [2] [Total: 6] L object

7 5 The diagram shows a negatively charged metallic sphere held with an insulating handle. When the sphere is brought towards a metal plate, the sensitive galvanometer registers a momentary deflection. (a) Explain why the galvanometer registered a momentary deflection when the charged sphere was brought near. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… …………………………………………………………………………...………………[2] (b) Draw on the above diagram, the electric field set up between the sphere and the plate when the sphere was brought near. [1] (c) Describe what would be observed if the charged sphere was held in hand and moved towards the metal plate. Explain your observation. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… …………………………………………………………………………...………………[2] [Total: 5] metal plate sphere

8 6 The diagram shows an electrical circuit with different electrical components. The resistance of X is 2000 Ω and 400 Ω in dark and bright conditions respectively. (a) State the name of component X ……………………………………....…………….[1] (b) When S1 and S2 are opened in a bright room, calculate (i) the effective resistance of the circuit, effective resistance = ………………………..[2] (ii) the charge flowing through the battery in 2 minutes. charge = …………………………..[2] A1 D C 80 Ω 12 V A2 E S1 60 Ω 30 Ω S2 X

9 (c) When S1 and S2 are closed in a dark room, (i) calculate the power dissipated in X. power dissipated in X = …………………………..[2] (ii) Describe what measurements are taken and how they are used to find the energy produced by the 30 Ω resistor in 2 minutes. ………………………………………………………………………………....….. ………………………………………………………………………………....….. ………………………………………………………………………………....….. …………………………………………………………………..…………..….[2] [Total 9]

10 7 An electric kettle consists of two heating elements as shown in the diagram. The heating elements can be connected to the electrical mains supply of 240 V in various ways so that the heating power can be varied. (a) Complete the circuit so that the heating power is the maximum and the kettle is safe to use. [2] (b) The maximum heating power of the electric kettle is 550 W. Determine the fuse rating for the kettle. fuse rating = …………………………[1] (c) Draw, on the above diagram, the correct position for the fuse and switch. Explain your answer. ………………………………………………………………………………………….. ……………………………………………………………………………………..…[2] (d) Electrical energy costs $0.27 per kWh. Calculate the cost of using the kettle when switched on for 40 minutes every day in one month (i.e. 30 days). cost = ……………………………….[2] [Total: 7] L N E heating elements

11 8 (a) The diagram shows a mechanical device. (i) State the name and function of part Q. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. ……………………………………………………………………….………….[2] (ii) Suggest one modification to the above set-up so that coil will rotate faster in the opposite direction. …………………………………………………………………………………….. ……………………………………………………………………….………….[1] (b) The diagram shows a beam of positively-charge particles passing between the poles of a powerful U-shaped electromagnet. (i) State the polarity of the magnet at X and Y. …………..………………………………………………………….…………..[1] magnified view screen to supply positively charged particles Fig. 8.1