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GIRLS’ SECONDARY – MRIEĦEL

HALF YEARLY EXAMINATION 2015/2016

TIME: 1½hrs FORM 3 Track 3

Name: ________________________ Class: _______ Index: _____

Notes for candidates:

Answer all the questions.

Write down your answers in the spaces provided.

The use of a calculator is allowed.

Whenever necessary take g to be 10N/kg.

Formulae that can be used are listed below:

Measurements V = l x b x h A = l x b

Density ρ = m ÷ V

Forces W = mg

Pressure P = F ÷ A P = hρg

Moments Moment = Force x perpendicular distance from the pivot

Question No. 1 2 3 4 5 6 7 8 Theory Practical

Mark

Final

Mark

Maximum

Mark 8 8 8 8 8 15 15 15 85 15 100

Score

For office use only

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Section A - This section carries 40 marks

Question 1: This question is about measurements (1mark for each answer)

a. Complete the following –

i. 250m = _________________ cm

ii. 0.35kg = ________________ g

iii. 2hrs = ___________________ minutes = ______________________ seconds

b. Martha needs to do an experiment in the lab:

i. To find the volume of some water, she uses a ________________________.

ii. To find the mass of a small rock, she uses a _____________ _____________.

iii. To find the volume of a large rock, she uses a ________________________.

c. Alessandro is interested in doing a marathon. To keep track of his speed he

needs to record the distance and the time.

An appropriate apparatus used to measure the time is a ____________________.

(Total: 8 marks)

Question 2: This question is about density

a. Complete the following table (show your working in the lines provided):

(2 marks for each answer)

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

Mass (g) Volume (cm3) Density (g/cm3)

200 17.64

9.8 7.85

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b. Luca was given a pendant with a back and front surface area as shown in the

diagram below. (Note: Diagram is not to scale)

ii. If the thickness of the pendant is 0.2cm, find the volume of the pendant.

____________________________________________________________________________

____________________________________________________________________(1 mark)

iii. If the mass of the pendant is 19.3g, find the density of the pendant.

____________________________________________________________________________

____________________________________________________________________________

___________________________________________________________________(2 marks)

(Total: 8 marks)

Question 3: This question is about pressure

a. A student with a mass of 60kg falls asleep on his four-legged

chair of mass 5kg. Each leg of the chair has a surface area of

0.0002m2 in contact with the ground.

i. Find the total WEIGHT of the student and the chair together.

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________(2marks)

i. Use the diagram to find the front

surface area of the pendant

____________________________________

____________________________________

____________________________________

____________________________________

____________________________(1 mark)

1cm

1cm

3cm

2cm

Name: Class:

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ii. Find the total surface area of the chair in contact with the ground.

____________________________________________________________________________

____________________________________________________________________________

_____________________________________________________________________(1mark)

iii. Hence, find the pressure exerted by the student and chair on the

ground.

____________________________________________________________________________

____________________________________________________________________________

___________________________________________________________________(3 marks)

b. Which of the following statements shows the highest pressure upon the

ground? (Mark your answer with an ‘X’)

A 7000-kg elephant with total area 0.5m2 in contact with the

ground

A 65-kg lady in high heels with total area 0.005m2 in contact with

the ground

(Total: 8 marks)

Question 4: This question is about forces

a. Tick whether the following statements are TRUE or FALSE (4 marks)

STATEMENT TRUE FALSE

Friction is a force which occurs between two surfaces

rubbing against each other.

Weight is a vector quantity.

Our weight on the moon does not change; it is our mass

which changes.

On a flying plane there is no gravitational force.

(2 marks)

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b. The diagram below shows a stationary car, draw and label the forces acting

on the car:

(3 marks)

c. Find the resultant force acting on the rope shown below, stating its size and

direction.

Resultant force = _______________________________ (1 mark)

(Total: 8 marks)

Name: Class:

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Question 5: This question is about moments

The diagram below shows a uniform metre ruler AB resting at its centre on a pivot. A

weight of 20N is placed 0.3m away from the pivot. Another weight ‘X’ is placed 0.4m

away from the pivot on the opposite side to keep the rule in equilibrium.

a. Calculate the size of weight X:

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

_____________________________________________________________(3 marks)

b. Underline the correct answer: (5 marks)

i. The direction of the moment created by weight X is (clockwise,

anticlockwise).

ii. The sum of the total clockwise moments is (greater than, equal to,

smaller) than the sum of the total anticlockwise moments.

iii. If the distance of X from the pivot is reduced to 0.2m, for the system to

remain in equilibrium, the distance of the 20N force from the pivot must

be (0.15m, 0.10m).

iv. If weight X is doubled, for the system to remain in equilibrium, the 20N

force must be replaced by another one of size (10N, 40N).

v. If weight X is halved, for the system to remain in equilibrium, the 20N

force must be replaced by another one of size (5N, 10N).

(Total: 8 marks)

0.3m 0.4m

20N X

A B

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Section B - This section carries 45 marks

Question 6: This question is about pressure

Two physics students were doing an experiment to prove that in a liquid pressure

increases with depth. Using a pressure sensor and a large measuring cylinder filled with

liquid, they managed to obtain the following results:

Pressure by liquid

(Pa) 0 0.5 1.0 1.5 2.0 3.0

Height of liquid

(m) 0 0.05 0.10 0.15 0.20 0.30

a. On a graph paper, use the above results to plot a graph of Pressure (Pa) on the y-

axis against Depth (m) on the x-axis.

(4 marks)

b. Using any two values from the above table, calculate the density of the liquid.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

________________________________________________________________________(3 marks)

c. Using the graph, what is the pressure in the liquid at a depth of 0.35m?

_________________________________________________________________________(1mark)

d. Using the graph, what is the depth of liquid at a pressure of 2.5Pa?

_________________________________________________________________________(1mark)

e. What would be observed if the experiment is repeated with a less dense liquid?

_________________________________________________________________________________

_________________________________________________________________________(1 mark)

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f. What would happen to the pressure if the same experiment had to be done on

another planet where the gravity is less than 10N/kg?

_________________________________________________________________________________

________________________________________________________________________ (1 mark)

g. What would happen to the pressure if the same experiment had to be done using a

wider measuring cylinder? Explain.

_________________________________________________________________________________

_________________________________________________________________________________

________________________________________________________________________(2 marks)

h. The students found the information shown below on the internet:

Liquid Density

Oil 0.95 kg/m3

Orange juice 1.1 kg/m3

Water 1.0 kg/m3

Which liquid must have been used for this experiment?

_________________________________________________________________________(1mark)

i. After the experiment, the teacher asked the students if there is any pressure acting

on the water, and if yes what is it called. Give an answer for this question.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________(1mark)

(Total: 15 marks)

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Question 7: This question is about moments

Paul found a uniform meter ruler weighing 0.5N. He also found some string, a small empty

tin, and some 100g masses. Paul set the equipment as shown in the diagram below:

a. Mark clearly with a letter ‘C’ the centre of gravity of the ruler. (1 mark)

b. State the law of moments.

_________________________________________________________________________________

_________________________________________________________________________________

________________________________________________________________________(2 marks)

c. Paul filled the empty tin with water until the total weight of tin and water is 3N. Then

he placed it 30cm away from the string as shown in the diagram. Calculate the

distance at which he has to place 2 of the masses to balance the ruler.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

________________________________________________________________________(3 marks)

d. On the diagram above, mark and label all the forces acting on the plank, and

calculate the respective tension force when the system is in equilibrium.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________(3marks)

Tin

Ruler

String

100g masses

30cm

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e. Paul now adds another 100g mass on the previous two, for a total of 300g at the

same distance from the pivot as before. Calculate the extra weight of water that

Paul needs to add in the tin in order to balance the system again.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

________________________________________________________________________(4 marks)

f. Paul then removed all the masses and the tin from above the ruler. After removing

everything, does the ruler remain balanced? Explain.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________(2marks)

(Total: 15 marks)

Question 8: This question is about Hooke’s Law.

a. State Hooke’s Law.

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________(2 marks)

b. What do you understand by the term elastic limit?

______________________________________________________________________________

______________________________________________________________________________

_____________________________________________________________________(2 marks)

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c. In the space provided, draw and label the set up needed to perform an

experiment to prove Hooke’s Law.

(4 marks)

d. Complete the following: (2 marks)

The _____________ was set up as shown in the diagram above. The ______________

length of the spring was measured and recorded in a table. A 1N weight was hung

and the new _______________ of the spring was recorded. These two values were

subtracted and the ______________ of the spring was found. This procedure was

repeated with different weights.

e. Complete the following table: (2 marks)

Applied force (N) 0 1 2 3

Length of spring (cm) 5 7 9

Extension (cm) 6

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f. Write two precautions to ensure an accurate result.

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________(2 marks)

g. Mark with a letter ‘E’ on the graph below the elastic limit (1 mark)

Extension (cm)

Weight (N)