2014 Year 9 Final Physics.pdfView Download

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2014 Annual Examinations

Subject: Physics Time: 2 Hours

Teacher’s Name: Mr GJ Zahra, Mr D Mangion No. of Pages: 11

Name & surname: __________________________ Class: Year 9

 This paper consists of ten questions. Each question carries a total of ten marks.

 Answer all questions in the space provided.

 Mark allocations are shown in brackets next to each question.

 Write down your Name, Surname and Class on all your answer sheets.

 You are requested to show all working and write down the units where necessary.

 You are reminded of the necessity of good English and orderly presentation of your work.

 In calculations, you are advised to show ALL the steps in your working.



Where necessary, take g, acceleration due to gravity, to be 10 m/s2.

Below is a set of formulae that you might find useful during the examination:

Density

Pressure

Energy & Work

Force

Heat

Item Lab

Report 1 2 3 4 5 6 7 8 9 10 Total Total

Max.

Mark 15 10 10 10 10 10 10 10 10 10 10 115 %

Actual

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1. David wants to compare the density of fresh water with that of sea water. He collects

samples of rain water and samples of sea water.

a. What instrument is used to find the volume of sea water?

__________________________________________________________ (1)

b. Describe how David finds the mass of the sample of sea water. Remember to

name the instrument used.

_____________________________________________________________

__________________________________________________________ (4)

c. David obtains the following results. Calculate the density of both sea water

and fresh water.

Liquid Mass (g) Volume (cm3)

Fresh Water 49.5 49.3

Sea Water 50.0 48.2

_____________________________________________________________

__________________________________________________________ (3)

d. The Dead Sea is extremely salty. Explain, using the values above, whether it

is less or more difficult for someone to float in the Dead Sea.

_____________________________________________________________

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2. Motorcycles have separate front and back wheel

hydraulic brakes. The master cylinder for one of

the brakes has an area of 12.5 cm2.

a. Convert the area of the master cylinder to

m2.

_________________________________

______________________________ (1)

b. Calculate the pressure in the master cylinder if a force of 10N is applied by the

motorcyclist.

_____________________________________________________________

__________________________________________________________ (2)

c. What is the pressure in the hydraulic fluid?

__________________________________________________________ (1)

d. The master cylinder is connected to secondary piston. The total force applied

by this piston is of 35N. Calculate the area of the secondary piston.

_____________________________________________________________

__________________________________________________________ (2)

e. Rear tyres of cars are fitted with drum brakes where each wheel has two

pistons that push against a drum. Explain the advantage of such a system.

_____________________________________________________________

__________________________________________________________ (2)

f. Give two reasons why hydraulic oil, rather than another liquid such as water, is

used for hydraulic machines.

_____________________________________________________________

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3. Door closers typically have a spring in them that is stretched when the door is

opened. This then pulls the door back in place once no force is applied. There are

two different mechanisms that slow this process to avoid the door being slammed.

a. The spring in such a mechanism obeys Hooke’s Law. Define Hooke’s Law.

_____________________________________________________________

__________________________________________________________ (2)

b. A door spring has an extension coefficient of 3 N / cm. If the spring extends by

5 cm when the door is opened, calculate the force needed to open the door.

__________________________________________________________ (1)

c. Suggest a disadvantage of using a stiffer spring.

__________________________________________________________ (1)

d. The spring is limited from extending more than 5.5 cm by a metal frame. What

would happen if the spring is extended more?

_____________________________________________________________

__________________________________________________________ (2)

e. Given the information in (a) and (b), sketch a graph to show how the extension

of the spring varies with the force applied. (2)

f. Jeremy thinks that it would be better to place the spring mechanism further

away from the hinge. Discuss.

_____________________________________________________________

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4. This question is about moments. A lever winch is used to lift a wooden pole of mass

400kg. The distance between the pivot and the centre of gravity of the wooden pole

is 3cm.

a. What is meant by the term centre of gravity?

_____________________________________________________________

__________________________________________________________ (2)

b. Calculate the weight of the wooden pole.

_____________________________________________________________

__________________________________________________________ (2)

c. Calculate the moment exerted by the pole around the pivot.

_____________________________________________________________

__________________________________________________________ (2)

d. Calculate the force that needs to be exerted on the handle if it lies 0.35 m from

the pivot.

_____________________________________________________________

__________________________________________________________ (2)

e. The diagram below shows the same lever winch in different positions. Explain

in which position it is easier to apply most force.

_____________________________________________________________

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5. In his diving trip to the Um El Faroud wreck at Wied iz-Zurrieq, Miguel noted how the

pressure varied with depth. He recorded the following values.

Depth (m) 8 12 22 28 34

Pressure (Pa) 180 000 225 000 325 000 400 000 450 000

a. Plot a graph of Depth (m) on the x-axis against Pressure (Pa or kPa) on the

y-axis. Start both axes from the origin. (4)

b. What is the relationship between pressure and depth?

__________________________________________________________ (1)

c. Use your graph to estimate atmospheric pressure.

__________________________________________________________ (1)

d. Calculate the gradient of the graph.

_____________________________________________________________

__________________________________________________________ (2)

e. Hence, or otherwise, calculate the average density of sea water during this

dive.

_____________________________________________________________

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6. Steve drives his remote controlled car on a straight, level road. The diagrams below

show the total forward and backward forces acting on the car at three different

stages as it moves forward.

a. Describe the car’s motion in

i. Diagram A: ____________________________________________ (1)

ii. Diagram B: ____________________________________________ (1)

iii. Diagram C: ____________________________________________ (1) b. Name two forces that may act in the opposite direction to the car’s motion.

______________________________________________________________

___________________________________________________________ (2)

c. Forces are vector quantities. Explain the phrase vector quantities.

______________________________________________________________

___________________________________________________________ (2)

d. Calculate the resultant force in Diagram A.

___________________________________________________________ (1)

e. Calculate the work done when the car is moved by 12m on application of this force

(as calculated in d).

______________________________________________________________

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7. This question is about energy. An object of mass 13 kg is allowed to slide along a

steep, rough slope 5m high.

a. Calculate the potential energy of the object at the top of the slope.

______________________________________________________________

___________________________________________________________ (2)

b. The velocity of the object at the end of the slope was 9.4 m/s. Calculate the

kinetic energy of the object.

______________________________________________________________

___________________________________________________________ (2)

c. Hence, calculate the percentage energy lost along the slope.

______________________________________________________________

___________________________________________________________ (3)

d. The same object is lifted to the same height of 5m.

i. What is the work needed to lift the object to this height?

______________________________________________________ (1)

ii. The object is then dropped. Predict, giving reasons for your answer,

whether the final speed reached by the object will be identical to, higher

than, or lower than 9.4 m/s.

__________________________________________________________

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8. This question is about sources of energy.

a. At the Power Station in Delimara, fossil fuel is burnt to turn the turbines in order to

generate electricity. Fill in the energy conversions in the flow chart drawn below

stating the type of energy in: (4)

b. Il-Partit tal-Baħar has promised that, if elected in the coming elections, it will

transform the Delimara power station to one operated by nuclear energy. You are

the spokesman for the Partit tal-Bahar. Briefly describe the relative disadvantages

of fossil fuels and the relative advantages of nuclear energy to convince the

electorate to vote you in office.

______________________________________________________________

___________________________________________________________ (4) c. The Partit tal-Ħaxix has slammed down your proposition and is arguing that Malta

should be entirely run by renewable energy sources. Name two such sources that

can be used in Malta and a disadvantage that they share.

______________________________________________________________

___________________________________________________________ (2)

i. Fossil Fuel ii. Turbine

iii. In Homes ii. Turbine

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9. This question is about heat. Luca sets up two conical flaks – one painted silver and one painted black – filled with the same volume of water, a heater and a

thermometer.

a. How is heat transferred:

i. From the heater to its metal core? _________________________

ii. Inside the water? _________________________ (2)

b. Luca switched on the heater, rated 60 W for 5 minutes. Calculate the total energy

used up by the heater.

______________________________________________________________

___________________________________________________________ (2)

c. Given that each container contained 0.25 kg of water at an initial temperature of

20⁰C, calculate the final temperature reached by the water (specific heat capacity

for water is 4,200 J/kg⁰C).

______________________________________________________________

___________________________________________________________ (3)

d. The final temperature reached by the water in both containers was 34 ⁰C. Give

reasons to explain why this value is different from that calculated in (b).

______________________________________________________________

___________________________________________________________ (2)

e. After some time, Luca notes that the temperature reading in the black container is

lower than that in the white container. Explain this observation.

______________________________________________________________

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10. This question is about earth and the universe.

a. Name the eight planets in the solar system starting from the one that is closest to

the sun. (4)

i. ii. iii.

iv. v. vi.

vii. viii.

b. The solar system is home to other objects such as Ceres, Makemake, Eris and

Haumea which are called dwarf planets. By referring to the definition of a planet,

explain why these objects are not considered to be planets.

______________________________________________________________

___________________________________________________________ (3)

c. More than 900 planets have been found beyond our solar system. The biggest

planet, DENIS-P J082303.1-491201 b, was discovered in August 2013, is 29

times as heavy as Jupiter and lies 67.7 light years from Earth. Given that the

speed of light is 3 x 108 m/s, calculate the distance between Earth and DENIS-P J082303.1-491201 b giving your answer in metres.

______________________________________________________________

___________________________________________________________ (3)

2014 Year 9 Final Physics.pdfView Download

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End of physics examination!