ACSI 2019 Y3 IP Physics Paper2 Answers

1 END-OF-YEAR EXAMINATION 2019 YEAR 3 INTEGRATED PROGRAMME PHYSICS PAPER 2 Mark Scheme Monday 7 October 2019 1 hour 45 minutes INSTRUCTIONS TO STUDENTS Write your index number in the box provided on the top right corner of this page. Do not open this booklet until you are told to do so. Section A Answer all questions in the spaces provided in the paper. Section B Answer all questions in the spaces provided in the paper. INFORMATION FOR STUDENTS Candidates are reminded that all quantitative answers should include appropriate units. Candidates are advised to show their answers in a clear and orderly manner as more marks are awarded for sound use of physics than for correct answers. The number of marks is given in brackets [ ] at the end of each question or part question. Calculators are allowed for this paper. Take g = 10 N/kg. There are 18 pages. Section A [50 Marks] Marks Awarded Section Marks A B Penalty Sig. Fig. Units TOTAL SCORE Index Number

2 A1 A 6.0 kg parcel is dropped off vertically from a helicopter 800 m above the ground. Its parachute is activated some time after the fall. The speed -time graph for the first 25 seconds of its journey is shown in Fig. A1.1. Fig. A1.1 (a) Explain what is meant by “The Earth’s gravitational field strength has a magnitude of 10 N kg-1”. [1] There is a force of 10 N acting on per unit mass of 1 kg. (b) Explain, in terms of forces, why the parcel’s velocity increased immediately after being dropped. [2] The weight of the parcel is larger than the air resistance acting on it. There is a net force in the downwards direction and hence the parcel’s velocity increases immediately. (c) State the time at which the parcel first achieves terminal velocity. [1] 10 s speed / m s-1 time / s

3 (d) Draw a labelled diagram to show all the forces that act on the parcel at t = 15 s. Indicate the values of these forces on your diagram. [2] Correct direction of arrows, correct values indicated. eeoo (e) As the parcel falls, the Earth exerts a downward force on the parcel. Name the reaction force. [1] (upwards) Force by parcel on Earth. Weight = 600 N Air Resistance = 600 N

4 A2 A ball of weight W is suspended by two ropes as shown in Fig. A2.1 (not drawn to scale). The tension in the ropes are 870 N and 500 N. Fig. A2.1 (a) What is the resultant force acting on the weight W? [1] 0 N (b) By means of a scaled diagram, determine the weight W. State the scale used. [4] Scale : scale: 1.0 cm rep 10 N [A1] Correct diagram with arrows W = 1000 N (accept from 950 N to 1050 N) 870 N 500 N 60  30 

5 (c) State the effect on the tension of each rope when t