nas my2010 1e science mark scheme

8/2/2019 Nas My2010 1e Science Mark Scheme

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Section A: MCQ (30 marks)

Choose the most appropriate answer for each question and indicate the

corresponding letters, A, B, C or D in the OAS.

Which of the following is not a benefit of technology to humankind?

A Advancement of medicinal research to fight diseases.

B Advancement of nuclear research for production of electrical energy.

C Advancement of nuclear research for production of atomic bombs.

D Advancement of communication tools for rapid dissemination of information.

A good scientist possesses a spirit of inquiry which does not consist of the following.

A creativity, open-mindedness and patience.

B integrity, keen observation and perseverance.

C analytical mind, subjectivity and determination.

D resilient, never-say die attitude and impartial.

Which of the following should not be carried out in the lab?

A Washing all apparatus after use.

B Pouring unused excess chemicals back into their containers to prevent

wastage.

C Turning off Bunsen burner after use.

D Keeping the work station neat and tidy at all times.

Which of the following is a correct description of the round-bottomed flask?

A For mixing and heating chemicals to produce a gas when heating is required.

B For mixing and heating chemicals to produce a gas when heating is not

required.

C For collecting and holding liquids.

D For containing small amount of chemical substance.


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During an experiment, the conditions that we purposely arrange to be the same

through out the experiment are known as

A controlled variables.

B independent variables.

C dependent variables.

D the control.

The picture shows a person measuring the temperature on the alcohol thermometer.

What is one precaution she needs to take to ensure an accurate reading?

A To shift the eye to ensure no parallax error.

B The eye level must be at the bottom of the meniscus.

C The eye level must be horizontal and at the bottom of the meniscus.

D To ensure that both eyes are open to prevent parallax error.

Carol wishes to find out if her bottle can contain the whole can of grape juice she hasbought. It would be most helpful if she knows the of the bottle.

A surface area

B diameter

C volume

D depth

The depth of a 150 ml bottle is measured to be 13.45 cm. Which of the following is the

most suitable instrument to measure the depth?

A internal callipers.

B rule.

C vernier callipers.

D measuring tape.

Which of the following is an instrument used for measuring mass?


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A Extension spring balance.

B Compression spring balance.

C Beam balance.

D Weighing machine.

What is the zero error shown on the vernier callipers below?

A -0.04 cm

B +0.04 cm

C -0.06 cm

D +0.06 cm

A length of wire is wound tightly round a pen as shown in the diagram. The turns are

next to each other but do not overlap. When there are 700 turns of the wire, the

length of pen covered by the wire is exactly 4.9 cm.

What is the average diameter of the wire?

A 0.007 mm

B 0.07 mm

C 0.49 cm

D 14.3 cm

Adrian can type a total of 120 words every 2 minutes and Elisa can type 360 words

every 5 minutes. What is the average rate that both of them can type?

A 68.6 words/min

B 66 words/min

C 1.1 words/sec

D 1 word/sec

Which car has the highest fuel consumption rate?

Car Fuel consumption rateA 20 km for 2.5 litre


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B 35 km for 2 litre

C 120 km for 5 litre

D 13 km for 1 litre

Alfred leaves his house at 4 pm and reaches the school at 4.20 pm. He walks at an

average speed of 4.8 km/h. How far is the school from his house?

A 0.24 km

B 1.6 km

C 4.17 km

D 96 km

Which of the following will give the most accurate timing for a 400 m race?

A Mechanical stopwatch.

B Electronic stopwatch.

C Mechanical stop clock.

D Digital clock.

Tap A takes 5 minutes to fill a 3000cm3 container while Tap B fills a 5000cm3

container in 500 seconds. Which tap has a faster rate of flow?

A Tap A.

B Tap B.

C Both flow at the same rate.

D It is not possible to compare the rate because the two containers are not of

the same size.

Which of the below is a correct description of weight?

A The amount of substance in the body.

B The pressure exerted by a body.

C The space occupied by the body.

D The gravitational force on the body.


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Which of the following is not true of the effects of a force?

A Size of an object can be changed.

B Object can speed up.C Mass of an object can change.

D Object can change its direction.

The following statements correctly describe friction except

A Friction always opposes motion.

B Friction is needed to help us walk.

C Friction can be completely removed in daily living.

D Friction will cause the flow of water to slow down.

What is the difference between magnetic force and gravitational force?

A Gravitational force always attract while magnetic force always repel.

B Gravitational force always repel while magnetic force always attract.

C Magnetic force exist between magnets while gravitational force exist between

planets.

D Magnetic force will cause the flow of water to speed up while gravitational

force will cause water to slow down.

Alan starts the car engine and begins to drive out of the car park. Which of the

following shows the correct energy conversion?

A Chemical energy sound energy + heat + kinetic energy

B Kinetic energy Chemical energy + sound energy + kinetic energy

C Potential energyKinetic energysound energy + heat.

D Heat energy sound energykinetic energy

A parachutist descends from the sky. Which of the following forces is he

experiencing?

A Frictional Force.

B Gravitational force and air resistance.

C Gravitational force.

D Air pressure and wind forces.

What is true about different types of sources of energy?


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A Both renewable and non-renewable sources of energy are easily available.

B Non-renewable sources of energy are often harmless to the environment.

C Renew able sources of energy can be limited by the physical location of a

country.

D A country cannot use both renewable and non-renewable sources of energyat the same time.

The diagram shows a piece of spring with a 1 N weight hanging on it. The weight is

pulled down a certain distance and released and the spring starts to oscillate up and

down, making a certain sound in the process. Explain why the spring eventually

comes to a stop.

A The 1 N weight will slowly overcome the elastic potential energy in the spring.

B Gravitational potential energy is greater than the kinetic energy of the weight.

C Elastic potential energy in the spring is lost to kinetic energy.

D Energy is used to do work against air resistance and converted to sound.

Which statement below is true about heat energy?

A The amount of heat in a body is the same as its temperature.

B Heat energy flows from an object of higher temperature to lower temperature.

C Heat energy from the surrounding falls on the solar panel to give us electricity.

D A glass of cold water at room temperature loses heat energy steadily as its

temperature rises.

Which statement is true about the conservation of energy?

A Energy can be destroyed or created and changed to different forms.

B Energy can not be destroyed or created but only changed to different forms.


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C Each time I bounce a ball, sound energy is been conserved and changed to

kinetic energy.

D Energy is conserved whenever we use petroleum to start our car engine.

A boy pushes against a thick wall with a force of 200 N for 3 minutes. What is thework done by the boy?

A 36000 J

B 600 J

C 200 J

D 0 J

Jonathan carries his books weighing 10 N and walks 25 m. How much work was done

against gravity while carrying the books through out the walk?

A 0 J

B 10 J

C 25 J

D 250 J

Which of the following daily activities does not involve a turning effect?

A Climbing the stairs.

B Sweeping the floor.

C Opening the door.

D Riding a bicycle.

The set-up below shows two objects balanced on a piece of 1 m wooden plank. The

fulcrum is exactly at the 50 cm mark. Which statement correctly describes the set-up?


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A Both object L and object M has the same volume.

B Both object L and object M has the same mass.

C Anti-clockwise moment is greater than clockwise moment.D Clockwise moment is greater than Anti-clockwise moment.

----------------- End of Section A --------------------

Section B: Structured Questions (40 marks)

Answer all the following questions in the spaces provided.

1 Draw straight lines to match the hazardous symbols with the scenarios or

descriptions listed on the right. [5]

Mary accidentally spilled some

concentrated sulphuric acid. The

solution begins to corrode her skin and

she cries out in pain.

This symbol is found pasted on the pipe

in the science laboratory that brings us

the gas for lighting of the Bunsen

burner.


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John was carrying out an experiment

where the fume emitted irritates his

eyes.

Prisoners of war are brought into a gas-

chamber for execution where toxic

gases are released.

This symbol can be found outside a

hospital room where a patient is

undergoing X-ray.

2 (a) State the reading shown on the vernier calliper.

Reading:1.03 cm[1]

(b) A measuring cylinder contains a certain volume of water. A rock is fully

submerged into it and the water level rose to a new level. Show with working

provided, the volume of the rock.

1.5

m

1.5


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V= 40-30 = 10 cm3

Volume of rock:10 cm3. [2[

(c) The grid below shows an irregular shape of a certain area. Tick onto the grid

and estimate the area covered by the shape. Every grid square has an area

of 0.25 m2.

Area = 19 * 0.25 = 5 m2

Area:.4.75 m2.[2[

3 The diagram below shows the F1 grand Prix track in Singapore. Every driver has to

complete 20 laps of the circuit where one lap is about 12 km. At point number 07

and 16, there are a pit-stops where a driver can change his tyres.


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(a) A driver took 1 min and 50 s to complete the first lap. Calculate his speed in

m/s?

S= D/t

= 12000/110 [1]

=109 m/s [1]

speed: 109 m/s [2]

(b) During the 2nd lap, the driver made a pit-stop at point 07 and spent 30 s

changing his tyres there. His average speed for the 2nd lap was 75 m/s.

Calculate the time he spends driving on the track (excluding the time spent

at the pit-stop).

t = D/S

= 12000/75 [1]

= 160 s [1]

t = 160 30

= 130 s [1]

time:... 130 s [3]

The driver rate of fuel consumption was about 6 km/litre. How much fuel will

he need to complete the full 20 laps?


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total distance= 20 *12 = 240 km

fuel = 240/6 =40 l

Fuel:. 40 l .[2]

4 The picture below shows block A and B of identical weight of 20 N placed into a

tank filled with water.

(a) The bottom base area along side X of block A is 0.5 m2. Find the pressure

exerted by block A on the water.

P = F/A

= 20/0.5 = 40 Pa

Pressure: 40 Pa .... [1]

(b) The bottom base area along side Y of block B is 2.0 m2. Find the pressure

exerted by block B on the water.

P = F/A

= 20/2.0 = 10 Pa

Pressure: 10 Pa ..... [1]

(c) Explain why block A sink much deeper than block B.

Pressure exerted by A is higher than B.[1]

A

B

Side X

Side Y


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5 (a) State two daily examples when friction is useful to us.

Any two reasonable answers from textbook or workbook.

...

...

...[2]

(b) State one way to reduce friction.

.lubricant, rollers...........................................................................

......................................................................................................................[1]

(c) Describe two effects of forces when a driver slowly steps on the brakes of a

car and begins to turn the steering wheel to the left.

Slowing down an object & changing direction

......................................................................................................................[2]

6 (a) Aru and May are sitting on a sea-saw. What is the distance, d from the pivot

that May must sit for the sea-saw to be balanced?

200 X d = 250 X 1.2 [1]

d = 300/200

= 1.5 m [1]

d:....... 1.5 m.........[2]

(b) The diagram shows a man using a fishing rod.

effort


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(i) State what class of lever is the fishing rod.

3rd class......................................................................................[1]

(ii) Indicate on the above diagram, by using arrows, where the fulcrum

and effort are. [2]

7 The diagram below shows a hair dryer when it is switched on.

(a) State the energy conversion in the motor of the hair dryer is switch on.

Electrical energy kinetic energy + sound + heat

[any thing less than the above minus 1 m]..........................[2]

(b) Singapores main source of energy is from crude oil. Suggest two other

sources of energy that the country can use instead of crude oil.

solar energy, wind, biomass

......................................................................................................................[2]

8 The picture shows a basketball stationary at point A. It was released and hit the

fulcrum


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ground at point B. It bounces off the ground and reaches a height at point C.

(a) State what energy the basketball possess at point A.

Gravitational Potential Energy................................................................[1]

(b) As it falls from point A to point B, describe how the energy changes at mid-

air.

Gravitational Potential Energy changes Kinetic Energy

......................................................................................................................[1]

(c) What energy conversion takes place when the basketball hit the ground atpoint B?

Kinetic energy is changed to heat, sound and elastic potential energy.

[anything less than the above minus 1].........................................................[2]

(d) Explain why the basketball is only able to bounce back to point C which

height is lower than point A.

The total energy at point C is less than point A as energy is used to do work

against air resistance [1]and converted to sound and heat at point B [1]

Section C: Free Response Questions (30 marks)

Answer all the following questions in the spaces provided.

A

B

C


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9 (a) Mr Lee wants to investigate how the length of a pendulum, will affect the time

taken for it to complete one swing. He set up the experiment as shown

below.

The pendulum consists of a string attached to a metal bob of a certain

mass X gram. The length of the pendulum is given as L cm. One complete

swing is from A to B to C and back to A.

(i) Identify the independent variable in this experiment.

Length of pendulum............................................................................[1]

(ii) Identify the dependent variable in this experiment.

timing of one complete swing.............................................................[1]

(iii) Name two possible controlled variables in this experiment.

mass of bob + angle of swing

..........................................................................................................[2]

(iv) The pendulum started with a certain amount of gravitational potentialenergy at point A. After swinging for a while, it will come to a complete

A

B

C

L cm

Wooden

cork


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stop. Explain, in terms of energy, why does it come to a complete

stop.

GPE is used to do work against air resistance and friction of string

with the wooden cork.

(b) The diagram below shows a Bunsen burner which air-hole is completely

closed.

(i) Identify two characteristic of the above flame.

unsteady, produce lot of soot, not as hot,luminous...............................

. ...........................................................................................................[2]

(ii) Indicate on the diagram above, with arrows, the colours of different

part of the flame. [2]

Dark blue

orange


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10 (a) The table below shows the densities of various substances. Use the

information given to identify the unknown substances in each of the

cases below. [5]

Liquid Density (g/cm3) Solid Density (g/cm3)

Alcohol 0.79 Gold 19.3

Seawater 1.03 Ice 0.92

Glycerine 1.30 Wood 0.5

Mercury 13.6 Iron 7.8

Petrol 0.80

Petrol

Mercury

B

Wood

A

Glycerine

Mercury

Petrol

Gold

WoodW

Iron

E

D Petrol

Glycerine

GoldMercury

Seawaterice

C

A: .....Gold..................

B: ..alcohol............................

C: Glycerine..............................

D: .wood...........................

E: ..mercury..............................


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A piece of iron of volume of 20 cm3 has a mass of 158 g. Find its density.

d = m/v

= 158/20 = 7.9 g/cm3

density of iron:.. 7.9 g/cm3..[1]

(c) A piece of carbon of mass 220 g has a density of 2.2 g/ cm3. Find its volume.

v = m/d = 220/2.2 = 100 cm3

volume of carbon:.... 100 cm3.......[1]

(d) When the piece of iron and carbon is melted together, it forms an alloyknown as steel. Calculate the density of the steel.

total mass = 220 + 158 = 378 g [1]

total volume = 20 + 100 = 100 cm3 [1]

d = m/v = 378/120 = 3.15 g/cm3 [1[

density of steel:. 3.15 g/cm3......[3]


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11 (a) Identify the types of forces that are at work in the following scenarios. [5]

Situations Forces at work

Iron pins that are attracted to one

another.

magnetic force

Lighting a matchstick. friction force

Gripping a glass of water without it

slipping off the hand.

friction force

A satellite falling into the earth

atmosphere.

gravitational force

A maglev train that is running alonga track. magnetic force

(b) Mrs Wong is pushing her trolley full of grocery towards her car. The grocery

weighs a total of 400 N. Mrs Wong pushes the trolley with a force of 200 N

and approaches the car 4 m away.

(i) Calculate the amount of work done by Mrs Wong in pushing the

trolley.

w = f x d [1]

200 N x 4 = 800 J [1]

Work done:.... 800 J.......[2]

(ii) What is the work done by the grocery against gravity?

0 J......................................................................................................[1]

(iii) Mrs Wong could have pushed the grocery along the floor towards the

car. How has the trolley make work easier for Mrs Wong?

the rollers on the trolleys[1] reduce the frictional force[1].

-------- End of Section C -------

nas my2010 1e science mark scheme

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