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Form 2 Science Chapter 9 FORM TWO CHAPTER 9 STABILITY 1 Diagram 1.1 shows three wooden blocks labelled as A, B and C

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Form 2 Science Chapter 9

FORM TWO CHAPTER 9 STABILITY

1

Diagram 1.1 shows three wooden blocks labelled as A, B and C which are placed on a smooth board. One side of the block is lifted slowly to find out which block falls easily.

A

B

C

Diagram 1.1 (a) Which object is the most stable? …………………………………………………………………………………………………….. [1 mark] (b) Which object is the most unstable? …………………………………………………………………………………………………….. [1 mark] (c) Arrange the blocks in an ascending order of stability. ………………………………………………………………………………………………………. [1 mark] (d) Diagram 1.2 shows a wooden block.

Diagram 1.2

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(i) Draw a diagram to show how you would place the wooden block to make it more stable.

[1 mark] (ii) What are the factors that influence the stability of the wooden block?

(a) …………………………………………………………………………………………… (b) …………………………………………………………………………………………… [2 marks]

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2.

Model A, B and C in Diagram 2.1 have the same height.

A

B

C

Diagram 2.1

(a) (i) Which model is the most stable? …………………………………………………………………………………………………… (ii) Give a reason for the answer in (a)(i). .…………………………………………………………………………………………………... [2 marks] (b) (i) Which object is the least stable? ………………………………………………………………………………………………….. (ii) Give a reason for the answer in (b)(i). ……………………………………………………………………………………………………. [2 marks] (c) Draw lines and mark G to show the point of equilibrium of the objects shown in Diagram 2.3

Diagram 2.3 [2 marks]

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3.

(a) Diagram 3.1 shows two vases of flowers, P and Q.

P

Q Diagram 3.1

(i)

Based on your observation in Diagram 3.1, state the difference in the stability of vase P and vase Q. …………………………………………………………………………………………………… [1 mark]

(ii)

What inference can be made based on Diagram 3.1? …………………………………………………………………………………………………… [1 mark]

(iii)

State one hypothesis based on your observation in Figure 8.1. …………………………………………………………………………………………………… [1 mark]

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(b) A student carries out an experiment to investigate the situation in Diagram 3.1. Diagram 3.2 shows the apparatus set-up for the experiment.

Pulley Plasticine

Weights

Stick Diagram 3.2 The student takes the following steps:

Step 1: A lump of plasticine is made into a shape of a cylinder to form a model. Step 2: Four sticks of equal size are fitted into the four corners of the model to form the legs so that it can stand on the table. Step 3: A string is hooked to the model. The string then passes over a pulley fixed at the edge of the table. A dish is tied to the end of the string. Step 4: Weights are added to the dish until the model topples. Step 5: The weight needed to topple the model is then recorded. Step 6: Steps 2 to 6 are repeated using sticks of different lengths.

(i)

Record the weight needed to topple models P, Q and R in Table 3.3.

Pulley Plasticine 10

Stick

8 cm Model P

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Pulley Plasticine 10

Stick

20

12 cm

Model Q

Pulley Plasticine

Stick

5 10

16 cm

Model R Model

P

Q

R

Length of straws(cm)

8

12

16

Weight needed to topple model (N)

Table 3.3 [2 marks]

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Using Table 3.3, draw a bar chart to show the weight needed to topple the different models. Weight needed to topple model (N)

(ii)

70 60 50 40 30 20

[2 marks]

(c) State the relationship between the length of the sticks and the weight needed to topple 10 the model. ………………………………………………………………………………………………………. ……………………………………………………………………………………………………… Model [1 mark] (d) State the variables involved in this experiment. Manipulated variable:

……………………………………………………….

Responding variable:

……………………………………………………….

Controlled variable:

Size and shape of plasticine model

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[2 marks]

(e) Based on the graph, predict the weight needed to topple the model if the length of the stick is longer than 16 cm. …………………………………………………………………………………………………… [1 mark] (f) Based on the experiment, state the relationship between the position of the centre of gravity and the stability of an object. ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… [1 mark]

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4.

Diagram 4.1 shows four tables, P, Q, R and S. Q

S

P

R

Diagram 4.1 (a)(i) Which table is the most stable? …………………………………………………………………………………………………… [1 mark] (ii) Explain your answer in (a)(i). …………………………………………………………………………………………………….. ……………………………………………………………………………………………………. [1 mark] (b)(i) Which table is the least stable? …………………………………………………………………………………………………… [1 mark] (ii) Explain your answer in ( b)(i). …………………………………………………………………………………………………….. ……………………………………………………………………………………………………. [1 mark]

(c) Arrange the tables according to their stability in descending order.

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[2 marks] (d) Diagram 4.2 shows a racing car.

Diagram 4.2 How is a racing car designed so that it will not fall over easily in a race? ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… [2 marks]

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