HYSS PLM PHYSICS 6091 4G3 P2 [MS]

1 2024 Physics S4E PLM Hua Yi Secondary School HUA YI SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 SECONDARY 4E (PHYSICS) 6091 MARK SCHEME Q Answer Q Answer Q Answer Q Answer 1 D 11 A 21 D 31 B 2 B 12 A 22 B 32 B 3 C 13 D 23 D 33 A 4 C 14 C 24 B 34 C 5 C 15 D 25 C 35 A 6 D 16 A 26 A 36 A 7 B 17 C 27 D 37 A 8 A 18 A 28 C 38 D 9 A 19 A 29 A 39 D 10 C 20 D 30 A 40 D Section A [50 marks] Qn No. Answers Marks 1 (a) As the speed increases, the air resistance acting on the child and the sledge also increases. Hence the resultant force decreases and the acceleration decreases. From 24 to 26s, the forward force is equal to the backward force and the resultant force acting on the child and sledge is zero. Hence, there is no acceleration and it moves with a constant speed. Need to mention resultant force in each case to get the marks. B1 B1 (b) The gradient of the graph becomes zero/ graph become horizontal from t = 24 s to t =26 s. Need to state the time from t= 24s to 26s to get the mark. B1 (c) Distance travelled = Area under the graph = ½ x (30-26) x 15.2 = 30.4 m Since the sledge stops in 30.4 m, it will stop before hitting the wall which is 35 m ahead. M1 A1 (d) The energy in the gravitational potential store is transferred to energy in the internal store. OR Gravitational potential energy to thermal / internal energy Note: the speed is constant, there is no changes in energy in the kinetic store. Reject any answers that mention kinetic store. B1 (e) The child experience inertia where his body mass resists a change in state of motion / and continue to move forward. Inertia + resist a change in state of motion / continue to move forward B1 Total: [7]

2 2024 Physics S4E PLM Hua Yi Secondary School 2 (a) 6.0 s A1 (b) The rebound velocity of 30 m/s is lower/less than the initial velocity. OR The displacement traveled during rebound is less than the initial velocity. Accept distance instead of displacement. B1 (c) a = (v-u)/t a = (-40 – 40)/6 a = - 13.3 N/kg g = 13.3 N/kg Only accept positive gravitational field strength and unit m/s 2 is not acceptable. M1 A1 (d) The gradient / acceleration is constant so the ball did not reach terminal velocity / is free falling / experience no resistance. Need to have both. B1 Total: [5] 3 (a) As the boom angle increases, the perpendicular distance between the load and the pivot decreases. Since the moment is the product of the force and the perpendicular distance, a decrease in the perpendicular distance allows for an increase in the force (load) while maintaining the same moment. Hence, the maximum load the boom can support increases. Formula of moments = F x d is needed. B1 B1 (b) (i) Moment = F x d = 11 500 x 22 = 253 000 Nm A1 (b) (ii) By taking moments about X, Clockwise moments = Anti-clockwise moments 253 000 = W x 5 W = 50 600 N A1 Total: [4] 4 (a) mgh = ½ mv2 gh = ½ v2 v2 = 2gh = 2 x 10 x 1 = 20 v = 4.47 m/s M1 A1 (b) Work Done (friction) = mgh – 4.5 J = (4 x 10 x 1) – 4.5 = 35.5 J Work Done (friction) = friction x distance 35.5 = friction x 2 friction = 17.8 N M1 A1 Total: [4]

3 2024 Physics S4E PLM Hua Yi Secondary School 5 (a) F1/A1 = F2/A2 5 / 2 = F2 / 0.08 F2 = 0.2 N M1 A1 (b) (i) Mass = Density x Volume = 1 x (0.6 x 2) = 1.2 g A1 (b) (ii) WD = F x d = 5 x (0.6 x 10-2) = 0.03 J Need to convert cm to m. A1 (c) Volume = Cross sectional area x distance For the same volume of water, since the cross-sectional area of the nozzle is smaller than the barrel, the distance moved by the water at the nozzle must be greater than the distance moved at the barrel. Hence, the speed which is the distance moved by the water per second is greater at the nozzle. Reject answer that link area to pressure. (0 m) B1 B1 B1 Total: [7] 6 (a) (i) Vlamp = IR = 17.6 x 10-3 x 10 = 0.176 V Vthermistor = 1.5 – 0.176 = 1.32 V M1 A1 (a) (ii) Rthermistor = V/I = 1.32 / (17.6 x 10-3) = 75 Ω Temperature = 40 °C Allow full ecf M1 A1 (b) In convection oven, the heat is transferred from the hot air to the food via conduction. Since air is a poor thermal conductor, the rate of cooking food is slower. In infra-red toaster, the heat is transferred directly to the food using infra-red radiation at high speed. Hence, food is cook faster. 1 m – air is a poor thermal conductor 1 m – infra-red radiation travels at high speed. B1 B1 Total: [6] 7 (a) Lamp A Tungsten wire has a higher reisistivity and a coil filament is longer compared to uncoil one, hence resistance of lamp A is higher. No marks for Lamp A B1 B1 (b) When the lamps are connected in series, the effective resistance of the circuit increases. / the voltage across each lamp is lower. Hence the current passing through the lamps decreases / The emf is shared between the lamps. Temperature of the lamp decreases and the resistance of the lamp is lower as it is a non-ohmic conductor. To get the last mark, need to link back to lamp being non-ohmic. B1 B1 B1

4 2024 Physics S4E PLM Hua Yi Secondary School (c) The fuse will still melts/blows and the lamp appears off. However, the metal case is still live and can cause electrocution or shock Many did not mention about the lamp not working and so was not awarded 2 m. B1 B1 Total: [7] 8 (a) At least 3 points plotted at (6000, 800), (12000, 400), (18000, 200) and (24000, 100) Smooth curve drawn B1 B1 (b) 9600 years (Answers depend on graph) Unit must be stated. B1 (c) β particles are absorbed by the 5 mm thick metal causing a significant decrease in the count rate. Υ-radiation is able to pass through the metal, thereby still causing a count rate of 200 with the metal piece in place. B1 B1 Total: [5] 9 (a) Lenz’s law state that the direction of the induced current is such that its magnetic effect opposes the motion or change producing it. When the magnet approaches the solenoid , the current induced in the solenoid will flow in a direction to repel the incoming magnet. Similarly, when the magnet is leaving the solenoid, the current induced in the solenoid will flow in the opposite direction to attract the leaving magnet. This generates an alternating current. Reject 1 m if the Lenz’s law is stated incorrectly such as the direction of the induced current opposes the changes that produces it. B1 B1 B1 (b) The movement of the magnet causes the surrounding air to be displaced. Sound then travels in the form of a longitudinal wave , consisting of a series of compression and rarefaction. Sound energy is transferred from particles to particles through vibration until it reaches the person’s ear. B1 B1 Total: [5] 10 (a) When the switch is closed, an alternating current flow through the solenoid causing the solenoid to be magnetized with alternating poles attracting and repelling the magnet. When the magnet vibrates, it creates disturbanc