Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 1 of 10

.

Answer all questions.

You are requested to show your working and to write the units where necessary.

The use of a calculator is allowed.

When necessary, take g, acceleration due to gravity, as 10m/s2.

You may find some of these equations useful:

Density m = ρ V

Pressure F = p A p = ρ g h

Moments Moment = F x perpendicular distance

Force and Motion W = m g

Waves T = 1

𝑓

Number 1 2 3 4 5 6 7 8

Maximum

Mark

8 8 8 8 8 15 15 15

Actual

Mark

Total Theory Total Practical Final Mark

Actual Mark

Maximum Mark 85 15 100

SAN ĠORĠ PRECA COLLEGE

Ħ A M R U N S E C O N D A R Y S C H O O L

Subtitle Text

HALF-YEARLY EXAMINATIONS 2019

YEAR:9 SUBJECT: Physics TIME: 1½ hours

NAME & SURNAME: __________________ CLASS: _______ INDEX NO: ____

Level

Tr 3

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 2 of 10

Section A: This section carries 40 marks.

1. This question is about Measurements.

a) Fill in the following table: (4)

Term Symbol SI unit

Mass

t

Force

kg/m3

b) Write in standard form:

i) 54,200 = _____________________ (1)

ii) 0.0000687 = ___________________ (1)

c) Convert 30 minutes to seconds

_________________________________________________________________________(1)

d) Change 56g to kg

_________________________________________________________________________(1)

2. This question is about density.

a) Give 3 steps how to find the volume of a door key stating the instrument used to measure.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

_____________________________________________________________________ (3)

b) Which instrument must be used to find the mass of the key? (1)

___________________________________________________________________________

c) If the mass of the key is found to be 78g and its volume was found to be 10cm3, calculate

the density of the key. (1)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 3 of 10

d) Choose the material of this key from the following table: _____________________ (1)

Material Density (kg/m3)

Aluminium 2712

steel 7850

nickel 8908

water 1000

e) Would this key float or sink in water? Why?

____________________________________________________________________ (1)

f) Name the instrument used to measure the thickness of this key. (1)

___________________________________________________________________________

3. This question is about Forces.

a) Jo, Daniel and Helen are pulling a metal ring. Jo pulls

with a force of 100N in one direction and Daniel pulls

with a force of 140N in the opposite direction. If the

ring does not move, what force does Helen exert if she

pulls in the same direction as Jo? Draw arrows on the

diagram to help you. (2)

__________________________________________________________________________

b) Match the following two columns by writing the matching number in the third column.

1 Weight The pull of a string/spring

2 Friction The force of gravity due to the pull of the earth

3 Air resistance The contact force which opposes the Action

4 Tension The force which opposes motion when flying

5 Upthrust The force which resists motion when two surfaces

move against each other

6 Reaction The upward push of an object immersed in a

liquid

(6)

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 4 of 10

4. This question is about Moments.

a) What is meant by the moment of a force? (1)

___________________________________________________________________________

b) The see-saw in the diagram below is balanced when Shaun of mass 32kg sits at A, Tom of

mass 54kg sits at B and Harry sits at C.

i) Find Shaun’s weight. (1)

_________________________________________________________________

ii) Find Shaun’s moment about O. (1)

_________________________________________________________________

iii) Find Tom’s weight. (1)

_________________________________________________________________

iv) Find Tom’s Moment about O. (1)

_________________________________________________________________

v) Find Harry’s weight. (2)

_________________________________________________________________

_________________________________________________________________

_________________________________________________________________

vi) What is the total upward force on the central support of the see-saw? (1)

_________________________________________________________________

5. This question is about Pressure.

a) Fill in:

i) In fluids (liquids and gases), pressure acts in ______ directions and pressure

________________ as the depth increases. (2)

ii) Atmospheric pressure can be measured by a mercury ___________________.

A B

3m

O

3m

1 m

C

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 5 of 10

b) The height of the Mercury column for standard atmospheric pressure is 760mm. Calculate

the atmospheric pressure, in Pascal, if Mercury has a density of 13,534 kg/m3.

___________________________________________________________________________

___________________________________________________________________________

_________________________________________________________________________(2)

c) i) A gas is in a closed container. As the temperature increases, what happens to the gas

pressure in the container? (1)

___________________________________________________________________________

ii) The same amount of gas is transferred to a smaller closed container at a constant

temperature, what happens to the gas pressure inside the container? (1)

___________________________________________________________________________

d) The picture shows a rubber sucker used to attach a soft

toy to a window. Draw arrows on the picture and explain

why it becomes attached to the window. (2)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

Section B: This section carries 45 marks.

6. This question is about Pressure.

a) Define Pressure in solids both in words and in a mathematical formula. (2)

___________________________________________________________________________

___________________________________________________________________________

b) Describe an experiment of how we can calculate the pressure exerted by both of our feet

onto the ground when bare footed. Your description should include:

i) the Apparatus required (2)

___________________________________________________________________________

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 6 of 10

ii) a short Method (3)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

iii) the equation to be used in order to calculate the pressure exerted by both of our feet. (1)

___________________________________________________________________________

___________________________________________________________________________

c) Kate uses a pair of roller blades to go roller skating on Sunday

afternoon. Each roller blade has four small wheels as shown in the picture.

While roller skating, the area of each wheel in contact with the ground is

0.02𝑚 × 0.01𝑚 .

i) Calculate the total area of contact with the ground when she stands on

both feet upright with all eight wheels touching the ground. (2)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

ii) If Kate’s mass is 35kg, calculate the pressure that she exerts on the ground when she stands

upright with all eight wheels touching the ground. (3)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

iii) While roller skating, Kate can balance herself on just one foot. What happens to the

pressure exerted at this point? Explain your answer. (2)

___________________________________________________________________________

___________________________________________________________________________

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 7 of 10

7. This question is about centre of gravity and stability.

a) All objects can be balanced on a point called the centre of gravity. When balanced, all the

_______________ of the object seems to be concentrated at this point. A uniform metre ruler,

will have this point on its ___ cm mark. (2)

b) Draw a well labelled diagram of the apparatus set up to find the centre of gravity of an

irregularly shaped lamina. (2)

c) Describe the steps taken to find the centre of gravity of an irregularly shaped lamina. (3)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

d) Mark the centre of gravity of the shapes below. Show all your work. (2)

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 8 of 10

e) An object is ________________ if when tilted it goes back to its original position. (1)

f) State the 2 factors that the stability of an object depends on and how these vary for an

object to be stable. (4)

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

g) A cereal box is rotated in 3 different positions as shown below, in positions A, B and C.

Which position is the most stable and which other position is the least stable? (1)

Most stable: ____; Least stable: ____

8. This question is about Hooke’s law.

Keith hangs a helical spring to a retort stand as shown in the diagram. He starts to add

the masses gradually and the spring extends accordingly.

a) Keith thinks that the spring obeys Hooke’s law. What does this law state? (2)

__________________________________________________________________________________

__________________________________________________________________________________

A B

C

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 9 of 10

b) i) The table below represents the results of Keith’s experiment. Plot a graph of extension/cm on

the y-axis against Load/N on the x-axis. (5)

ii) From your graph, find the value of the force when the extension is 24cm? (1)

__________________________________________________________________________________

iii) From your graph, find the value of the extension when a force of 5N is placed on the spring? (2)

__________________________________________________________________________________

iv) What can you conclude about the relationship of the force and extension from 0 to 10N? (1)

__________________________________________________________________________________

v) Mark the elastic limit on your graph using letter E. (1)

vi) Does the spring return to its original length when unloaded if the elastic limit is exceeded? (1)

__________________________________________________________________________________

vii) What may happen to the spring if it is loaded beyond its elastic limit? (1)

__________________________________________________________________________________

viii) Does the spring continue to obey Hooke’s law beyond point E? _________________________ (1)

Extension/cm 0 7 15 23 30 38 50

Force/N 0 2 4 6 8 10 12

Physics Year 9 Tr 3 Half Yearly Examinations 2019 Page 10 of 10