2009 eoy sec 3 physics paper 2

This paper consists of 18 printed pages.

Name: _____________________________________( ) Class: 3/ ( )

Subject : Physics Paper : 5058/2 Level : Secondary Three (Special / Express)

Date : Thursday 15th Oct 2009 Duration : 2 hours 15 minutes

READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces at the top of this page and on any separate answer paper used. Section A Answer all questions.

Paper 1

Paper 2

Section A

9

10 Section B

11

Total 100

Section B Answer all questions. Question 11 has a choice of parts to answer. At the end of the examination, fasten any separate answer papers used securely to the question paper. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Candidates are reminded that all quantitative answers should include appropriate units and given in sensible significant figures. Candidates are advised to show all their working in a clear and orderly manner, as more marks are awarded for sound use of Physics than for correct answers.

NAN HUA HIGH SCHOOL END OF YEAR EXAMINATION 2009

Nan Hua High School End Of Year Examination 2009 Physics 5058/ 2

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Section A Answer all questions in this section

1. Figure 1 shows the positions of a ball as it rolled down a track. The ball took 0.50 s to roll from

one position to the next.

(a) Calculate the average speed of the ball in rolling from A to E.

average speed = ……………............[2]

(b) (i) Sketch a distance-time graph for the motion of the ball, as it travels from position A to E. [2]

(ii) How does the graph show that the ball is accelerating?

[2]

distance/ cm

time/ s


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2. Figure 2.1 below shows a gate which closes automatically after use. A heavy stone is attached by chains JK and KL to the top bar of the gate and to the top of a nearby vertical post. Opening the gate raises the stone. When the gate is released, the force exerted by the chain JK closes the gate. The weight of the stone is 120 N.

When the gate is closed, each chain is at 300 to the vertical, as shown in Figure 2.2. The vector sum of the tensions in the chains is equal to the weight of the stone. Draw, to scale, a vector diagram showing these forces and use your diagram to determine the tension in each chain.

tension = ……………................. [3]

Figure 2.1 Figure 2.2


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3. Figure 3 below shows an oil drum floating in water. Force F is the force acting upwards on the bottom surface of the drum caused by the pressure of the water. (a) On the figure above, draw and label an arrow X to show the force exerted by the air on the top surface of the drum, and an arrow W to show the weight of the drum. [2]

(b) Atmospheric pressure is 100 000 Pa and acts on the top surface of the drum and on the water surface.

(i) The drum has a top surface of area 0.30 m2. Calculate the force that the air exerts on

this surface.

force = ……………............[2]

(ii) The pressure in water increases by 10 000 Pa for each meter increase in depth below the surface. The bottom surface of the drum is 0.50 m below the water surface. Calculate the total pressure in the water at this depth.

total pressure = ……………............[2]

Figure 3


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4. An airplane passenger placed his baggage, of total mass 50 kg, onto a trolley as shown below in Figure 4. He applied a force F at the handle to raise the baggage to the horizontal position.

(The gravitational field strength is 10 N/kg)

(a) The letter ‘X’ marked on the baggage is its geometrical centre. Assuming that the baggage has a uniform mass, ‘X’ is where its centre of gravity is located.

Explain the meaning of the term centre of gravity.

[1]

(b)The axle of the wheel acts as a pivot. Calculate the moment of the baggage about this axle.

moment = ……………..................[2] (c) Calculate the minimum force required on the handle to keep the baggage horizontal as

shown.

force = ……………...............[2]

(d) The passenger was wheeling the trolley to a gate on level ground at a constant speed. He had to stop his trolley very abruptly because an air stewardess suddenly crossed into his path. The inertia caused the baggage to slide forward onto the ground. Explain the meaning of the term inertia.

[1]

Figure 4


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5. Figure 5 shows a mercury barometer on a day when the atmospheric pressure is 750 mm Hg. Vessel B has a cross-sectional area 4 times that of tube A. The difference in mercury level in A and B is shown below. (a) If more mercury is added to B such that the mercury level in A rises by 2.0 cm, what will

happen to the mercury at B? [1]

(b) If some air is introduced to the space above A, the difference in mercury level of A and B becomes 600 mm. Find the pressure (in mmHg) of the air in the space.

pressure =……………............... [2] 6. A power boat of mass 2 200 kg moves across a smooth lake. It starts from rest and is driven

by a constant force generated by a propeller. After travelling a distance of 500 m, the power boat travels at a constant speed.

The graph (Figure 6) below shows the total force opposing the motion of the boat against the

distance travelled by the boat.

Figure 5

Figure 6


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(a) State the constant force generated by the propeller as the power boat moves across the lake.

force = ……………...........’[1]

(b) What is the magnitude of the net force acting on the power boat at the 200 m mark?

net force = ……………......[1]

(c) What is the acceleration of the power boat at the 200 m mark?

acceleration = ……………......[2]

(d) Estimate the work done by the power boat against the opposing force in travelling a distance of 200 m.

work done = …………...............[2]

7. Figure 7 below shows a glass KLMN with a ray of light incident on side KN at an angle of incidence of 600. The refractive index of the glass is 1.50.

(a) Calculate the angle of refraction of the ray.

angle of refraction = …………............... [2]

Figure 7


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(b) Calculate the critical angle for a ray of light in this glass.

critical angle =……………............... [2] (c) Explain why the ray shown in the figure above cannot emerge from the side KL but will

emerge from side LM. [2] 8. A normal eye can focus light from a near object and from a far object. In this question, you may

ignore refraction of light at the cornea, as shown in the Figure 8a below.

The figure above shows rays of light from a near object hitting the lens of a normal eye, forming a sharp image.

(a) The image formed in the eye is smaller than the object. State another property of the image. [1]

(b) A short-sighted person can see near objects clearly but not far objects.

Figure 8b below shows how the lens of an eye with this defect would focus rays from a far object.

(i) A diverging lens can be used to correct this defect. State a property of the image

formed by a diverging lens.

[1]

Figure 8a

Figure 8b


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(ii) Figure 8c below shows parallel rays from a distant object entering the diverging lens. Complete the figure to show the probable paths of the light rays, and hence, indicate the principle focus, F. [2]

Section B

Answer all questions Answer only one of the two alternative questions in Question 11.

9. Spirit is one of NASA’s exploration rover used to explore the surface of the planet Mars and its

geology. To deliver the Spirit to Mars, a spacecraft is required. The spacecraft will consist of its cargo, in this case, the Spirit, a Lander, parachutes, a heat shield, a cruise stage and fuel for the mission. Their total mass is approximately 1 063 kg.

About 91 minutes before landing time (L), the spacecraft will begin a 14-minute rotation to orient its heat shield forward. 15 minutes before atmospheric entry, the protective heat shield encasing the Lander and rover will separate from the cruise stage, whose role will at that point be finished. Each cruise stage will ultimately impact Mars.

On arriving on planet Mars, the spacecraft will hit the top of the atmosphere, about 120 km above the surface, with a velocity of about 5 400 m/s. Although Mars has a much thinner atmosphere than Earth, the friction of travelling through it will heat and slow the spacecraft dramatically. The surface of the heat shield is expected to reach a temperature of 1,447 0C. By 4 minutes after atmospheric entry, the spacecraft’s speed will have decreased to about 450 m/s. At that point, about 8.6 km above the ground, the spacecraft will deploy its parachute. Within 2 minutes, the spacecraft will be bouncing on the surface.

The diagram on the next page shows the stages of entry, descent and landing of the spacecraft.

Figure 8c

F


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(a) The gravitational field strength on Mars is known to be 3.90 N/ kg. (i) Explain the meaning of the term gravitational field strength.

[1]

(ii) Using the information given, calculate the weight of the spacecraft on Mars.

weight = ……………............... [2]


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(b) After the parachute was deployed at 8.6 km above the surface of Mars, the speed of the spacecraft decreases, before it starts to fall at a constant terminal velocity. Explain why the spacecraft stops accelerating after sometime to travel at terminal velocity.

[2]

(c) As the spacecraft moves from the “Atmospheric Entry” Phase to the “Parachute Deployment”

phase, calculate the following:

(i) the change in kinetic energy of the spacecraft. kinetic energy = ……………...............[2] (ii) the change in potential energy of the spacecraft. potential energy = ……………............[2] (iii) the total work done against friction during this period.

work done = ……………....................[2] (iv) State an assumption you have made in your calculation.

[1]


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10. (a) The waves made by earthquakes can be recorded by an instrument call a seismometer. Figure 10.1 shows how a mechanical version work by way of a large mass, freely suspended. A rotating drum records a red line on a sheet of graph paper. If the earth moves the whole machine will vibrate too, but the large mass tends to stay still, so the drum shakes beneath the pen, recording a trace.

Figure 10.2 shows a trace recorded by the seismometer after an earthquake.

(i) Comment on the frequency and amplitude of the wave. [2]

(ii) Calculate the frequency of the recorded wave.

frequency = …………….....................[2]

(iii) Earthquakes produce transverse and longitudinal waves. Describe one way in which a transverse wave is different from a longitudinal wave.

[1]

Figure 10.2

Figure 10.1


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(b) A Tsunami was caused by a undersea earthquake 25 km away from island X. It produced huge waves of 10 m high when they reached the shore of the island and destroyed several villages along the coast of the island. The wavelength of the Tsunami in deep ocean waters is 120 km and its period is 1.05 hours.

(i) Why are waves produced by a Tsunami so destructive as they reach the shore of the

island? [1]

(ii) Calculate the speed of the Tsunami waves in deep ocean waters.

speed = ……………..........[2]

(iii) Determine the time taken by the Tsunami waves to travel from the earthquake location

to island X. You may assume that the wave speed is constant.

time = ……………............ [2]


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11 Either (a) State the Principle of moments. [1]

(b) Figure 11a below shows the essential features of a simple crane used for lifting blocks

which are attached to the hook H.

(i) With no blocks suspended from H, the crane arm balances horizontally when the

position of the concrete mass is adjusted so that d = 0.60 m. Calculate the moment of the weight of the concrete mass about the pivot P. [2]

A load of blocks is then attached to H. A mechanism on the right-hand side moves the concrete mass away from the pivot P. When d = 1.7 m, the crane is able to balance the load of blocks, as shown in Figure 11a above. (ii) State the moment due to crane-arm about P. [1] (iii) Calculate the weight of the blocks in this situation, as shown in Figure 11a above. [2]

(c) An electric motor is fitted at Q which, by shortening the chain, increases the height to

which the blocks can be raised. State whether a change in the height of the blocks would increase the moment of the weight of the blocks. Give a reason for your answer, [2]

Figure 11a


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Or Figure 11b shows part of a hydraulic braking system of a motor car.

(a) Explain why the downward force on the brake pedal causes the piston in the slave cylinder to move. [2]

(b) (i) Calculate the pressure in the brake fluid, in Pa ,when a force of 200 N acts on the

piston of the master cylinder which has an area of 20 cm2. [2]

(ii) The piston in the slave cylinder has an area 3 times that of the piston in the master cylinder. Determined the force on the slave cylinder when the force on the master cylinder is 200 N. [2]

(iii) If the piston in the master cylinder moves down 5.0 cm, determine the distance moved by the piston in the slave cylinder. [2]

Figure 11b

End of paper


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