GRADE 9 HOMEWORK ACTIVITES

GRADE 9 HOMEWORK ACTIVITES


TERM 2 WEEK 1

ACTIVITY 1

1.1 Underline the correct word in the brackets. (5)

1.1.1. When gas is compressed in a closed container, this system is called

(hydraulic/ pneumatic) system.

1.1.2. Liquid is (compressible / incompressible).

1.1.3. Air is (compressible / incompressible).

1.1.4. The force transfer in a hydraulic system is (greater than / less than) the force

transfer in a pneumatic system.

1.1.5. According to Pascal’s principle “when pressure is applied to a fluid, the force

is transmitted (equally / unequally) in all directions”.

1.2 Fill in the missing words.

1.2.1 In a hydraulic system with two equal syringes, we get __________________

distance and ___________________ force between the two syringes.

1.2.2 In a hydraulic system where movement is from a small syringe to a larger

syringe, the output distance is _________________ and the output force is

bigger.

1.2.3 When the output force is increased by the force transfer from the input force,

we call this _____________________________.

1.2.4 Newton is the unit in which _______________ is measured

1.3 Match COLUMN A with COLUMN B. Write only the letter of the alphabet (A –

E) in the ANSWER column. (5)

COLUMN A ANSWER COLUMN B

1.3.1 Cylinder A. It takes into account the area over which the force

is acting

1.3.2 Piston B. Stop air from flowing out.

1.3.3 Valves C. Is a pull or a push and changes the velocity of an

object.

1.3.4 Force D. Tubes to suck in the air or liquid.

1.3.5 Pressure E. Is found inside the tube to compress the air or push

the liquid.


TERM 2 WEEK 1

ACTIVITY 2

2.1 Complete the following paragraph by filling in the correct words in spaces.

Pneumatics makes use of ______________________ air. Air under pressure

provides a lot of energy so that ___________________ can be done. To keep air

under pressure we use a ______________________. A compressor uses an air

pump driven by an ________________________ motor. The air that is put under

pressure is stored in a metal tank called a _____________________. (5)

2.2 Answer the following questions about hydraulics.

2.2.1 What advantage does a hydraulic system have over a pneumatic system? (2)

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2.2.2 Name four examples of the use of hydraulics in everyday life. (4)

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2.2.3 What is an input cylinder in hydraulics called? (1)

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2.2.4 What is an output cylinder in hydraulics called? (1)

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2.2.5 What is hydrodynamics? (1)

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2.2.6 What is hydrostatics?

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2.2.7 What do we call the system which uses flowing water to turn turbines in order

to generate electricity?

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2.3 Match COLUMN A with COLUMN B. Write only the letter of the alphabet (A –

F) in the ANSWER column: (6)

COLUMN A ANSWER COLUMN B

2.3.1 Pneumatic system A. It can be compressed to take up less

space.

2.3.2 Hydraulic system B. It can also be called master cylinder or

input cylinder

2.3.3 Driver cylinder C. It cannot be pressed to take less space.

2.3.4 Driven cylinder D. It is a tube and syringe filled with a liquid

(water or oil).

2.3.5 Compressible E. The output cylinder or the slave cylinder

2.3.6 Incompressible F. It is a tube and syringes filled with air.


TERM 2 WEEK 2

ACTIVITY 1

1.1 Study the hydraulic system below and answer the questions that follow.

1.1.1 Use the picture above to explain how forces within a hydraulic system are

transferred. (3)

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1.1.2 Calculate the output force, if the input force is 50N, the input piston’s area is

100mm² and the output piston’s area is 800mm². (3)

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1.1.3 Draw a systems diagram for the above hydraulic system. (4)

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Input Process Output


1.2 In the hydraulic press below; a force of 100 N is applied to piston A and it

moves down 10 cm. Calculate the…

1.2.1 work done by both pistons. (3)

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1.2.2 pressure of the fluid. (3)

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1.2.3 Maximum force that is exerted on the load by piston B. (3)

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1.2.4 Distance travelled by piston B. (3)

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1.2.5 Mechanical advantage of the system. (3)

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1.3 In the hydraulic press below a force of 20N is applied to piston A. Answer the

questions that follow.

1.3.1 Calculate the work done by both pistons if piston moves down 15cm. (3)

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1.3.2 Calculate the pressure of the fluid. (3)

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TERM 2 WEEK 2

ACTIVITY 2

2.1 Complete the system diagram for the hydraulic system below when the piston

is pulled upwards. (6)

Input Process

2.2 Complete the system diagram of the hydraulic system below. (6)

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Input

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Process

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Output


2.3 Study the diagram of the hydraulic jack below and answer the questions that

follow.

2.3.1 Identify the interacting systems in the hydraulic jack. (4)

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2.3.2 What is the purpose of the larger piston in the system? (2)

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Input

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Process

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Output


2.3.3 What is the function of the one-way valve in the system? (1)

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2.3.4 What is the purpose of the release screw in the system? (3)

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2.3.5 Describe the mechanical advantage of the system. (2)

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2.4 Answer the questions about the two hydraulic systems below.

2.4.1 What is the function of the reservoir in these hydraulic systems? (3)

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2.4.2 Explain how the reservoir and the two valves help to increase the movement

of the output piston. (6)

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2.5 Study the hydraulic jack below and answer questions that follow:


2.5.1 Explain how the hydraulic jack above manages to lift a motor vehicle. (4)

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2.5.2 How does the motor vehicle get lowered again? (2)

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2.6 Predict and then work out the mechanical advantage in each of these cases

below. State whether Thabo and Cecilia will be successful

2.6.1 Thabo uses 20N to lift a space case of 40N using a syringe system. (4)

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2.6.2 Cecilia needs to move a crate of 500N upstairs and applies 250N effort. (4)

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2.7 Calculate the output forces on slave cylinders (A – C) below. Write your answer

in the boxes provided above the cylinders. (3)

6cm2 3cm2

50N

9 cm2 12 cm2

A B C Master


TERM2 WEEK 3

ACTIVITY 1

1.1 The following questions are based on the pulley system. Choose the correct

answer and cross the letter of your choice.

1.1.1 If the load in the pulley system is lifted 12cm, what distance (in cm) does the

rope, where effort is applied, move?

A. 2 cm B. 24 cm C. 72 cm D. 150 cm (1)

1.1.2 The mechanical advantage of the pulley system is:

A. 6 B. 25 C. 120 D 150 (1)

1.1.3 What is the mechanical advantage of the compound pulley shown below?

A. 1 B. 3 C. 4 D. 2 (1)

1.2 Calculate the mechanical advantage of the pulley below. (3)


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TERM 2 WEEK 3

ACTIVITY 2

2.1 Complete the table below for each of the mechanical systems illustrated. (12)

Illustration Name of

mechanical system

Where it is used in real life

function

A

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B

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C

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D

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2.2 The mechanism below is an important control device used in many systems.

2.2.1 Name the parts labelled A, B and C.

A. _______________________

B. _______________________

C. _______________________ (3)

2.2.2 What is the purpose of part C in the above mechanism? (1)

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2.2.3 Give ONE example of a device that uses this locking system (1)

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2.3 Most bicycles use rim brakes, where a braking force is applied to the rim of the

wheel. Give any TWO advantages of using rim brakes in bicycles. (2)

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2.4 Name each system in the space provided in the table: (4)

A. _____________

B._____________

C.____________

D. ______________

2.5 Complete the table by using the following labels to identify different parts of a

braking system of a car shown below. (5)

[brake fluid, brake pedal, disc, wheel cylinder, master cylinder]

PART NO. LABEL

2.5.1

2.5.2

2.5.3

2.5.4

2.5.5

2.6 Explain the difference in the terms “step up” and “gearing down” when using mechanical systems.

2.6.1 “step up” pulley system (1)

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2.6.2 “gearing down” gear system (1)

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TERM 2 WEEK 4

ACTIVITY 1

1.1 Match Column A with Column B. Write only the correct letter of the alphabet (A –

D) in Answer column. (4)

Column A Answer Column B

1.1.1 Wheels with teeth that mesh with each other. They change the speed and direction of a rotating shaft.

A. Bevel gear

1.1.2 These gears work on the screw principle. A rotation on the screw wheel causes a much slower rotation on the teethed wheel. The input and output shaft are at 90 degrees to each other.

B. Spur gear

1.1.3 A gear wheel and a toothed bar to change a rotary movement into a linear movement.

C. Rack and

pinion

1.1.4 These gear changes the direction of rotation through 90 Degrees. The teeth are angled at 45 degrees so that the gears fit together at right angles

D. Worm gear

1.2 Match Column A and Column B: Identify concepts from Column A and match

the correct definition from Column B by writing its corresponding letter. (5)

Column A ANSWER Column B

1.2.1 Gear chains A. Prevent movement

1.2.2 Rack and pinion

B. Two or more gears working together to influence motion

1.2.3 Gear systems C. Changes direction and speed of motion

1.2.4 Cleats D. Converts rotary motion into linear motion

1.2.5 Spur gear

E. Wheels or cylinders that have teeth that mesh together


1.3 Study the diagrams of the different types of gears and match them with the

correct object. Write the matching letter in the answer column. (5)

LETTER TYPE OF GEAR ANSWER OBJECT

A

B

C

D

E


TERM 2 WEEK 4

ACTIVITY 2

Read the statements/questions below and circle the correct letter (A – D) of the

alphabet. (7)

2.1 The mechanism for tuning the guitar is an example of which type of a gear

system?

A. Spur gear B. Bevel gear C. Rack and worm gear D. Worm and spur gear

2.2 This type of gear system is used to change the orientation of rotational movement through 90o. A. Spur gear B. Bevel gear C. Rack and worm gear D. Worm and spur gear

2.3 In the train gear system below

A. The idle gear changes the gear ratio.

B. Gears A and B rotates in different directions. C. The idle gear has no effect on the gear ratio. D. None of the above.

2.4 Which one is the best position to insert a one-way

valve in the pump system below?

A. B B. C C. D D. A

B

A

D

B

C

A


2.5 Which one of the following control devices controls the flow of hydraulic fluids in hydraulic systems? A. Cleats B. One-way valves C. Rachet and pawl D. Restrictor

2.6 How many times should the worm turn for the worm wheel to make one

complete revolution.

A. 40 B. 80 C. 5 D. 0.2

2.7 Who is applying less effort (i.e. has a mechanical advantage)?

A. B

B. C

C. A

D. NONE

GRADE 9 HOMEWORK ACTIVITES TERM 2 WEEK 4

ACTIVITY 3

3.1 Study the drawing of a simple gear train and answer the questions that follow.

‘A’ is the driver gear; ‘t’ is the number of teeth on each gear.

3.1.1 If A moves in an anti-clockwise direction, in which direction does the driven gear

move? (1)

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3.1.2 Calculate the mechanical advantage of this gear train. (5)

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3.1.3 What load would the driven gear be able to carry if we applied a force of 40N on the

driver gear? (3)

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3.1.4 What is the speed ratio of this gear train? (2)

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3.1.5 What is the force ratio of this gear train? (2)

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3.1.6 How much faster or slower is the driven gear than the driver gear? (2)

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✓t = 40 A t = 480


3.2 The diagram below shows a typical gear train. Gear A is connected to a motor. Study the diagram and answer the questions that follow. (When gear A rotates 10 times, gear B rotates 5 times)

3.2.1 Identify the DRIVEN gear. (1)

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3.2.2 Give a reason for your answer in QUESTION 4.1. (1)

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3.2.3 Gear A rotates in a clockwise direction. In which direction will gear B rotate? (1)

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3.2.4 Calculate the velocity ratio of this gear system if gear A has 20 teeth and gear

B has 40 teeth. (3)

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TERM2 WEEK 5

ACTIVITY 1

Draw the cube in double vanishing point perspective in the space provided below.

(6)

Label the vanishing points, and horizon line. (3)


TERM 2 WEEK 5 ACTIVITY 2 Redraw the following figure as a two-point perspective drawing in the space provided below. (14) Please note:

• the two vanishing points are provided

• the first construction line with its projection lines are provided

• show all projection lines in your drawing

• use dark continuous lines to finish off your drawing

• dimensions need NOT be exactly the same as in the example

VP 2 VP 1

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GRADE 9 HOMEWORK ACTIVITES