CHAPTER 9: STABILITY

9.1 STABILITY

STRUCTURE QUESTIONS

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) 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 from most stable to least stable.

[1 mark]

(d) Diagram 1.2 shows a wooden block.

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

[1 mark]

(ii) What are the factors that influence the stability of the wooden block?

(a) ……………………………………………………………………………………………

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

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

(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

[2 marks]

(d) Diagram 4.2 shows a racing car.

How is a racing car designed so that it will not fall over easily in a race?

…………………………………………………………………………………………………

…………………………………………………………………………………………………[2 marks]

OBJECTIVE QUESTION

1. What is another term for the point of equilibrium?A The universal point B The center of oscillationC The point of weight D The centre of gravity

2. Which of the points labelled A, B, C or D, is the point of equilibrium of the chairshown in the figure below?

3. Among the following tables, which is the most stable?

4. Among the following objects, which is the most stable?

5. The stability of an object depends on the I base area II mass of the object III position of the centre of gravity A) I and II only B) I and III only C) II and III only D) I, II and III

9.2 APPRECIATING THE IMPORTANCE OF STABILITY

STRUCTURE QUESTIONS

1.Diagram 1.1 shows the position of conical flask.

Diagram 1.1

(a) What happen if we tilt the conical flask slowly?

…………………………………………………………………………………………..[1 mark]

(b) Give your reason for 1 (a).

…………………………………………………………………………………………..[1 mark]

(c) Diagram 1.2 shows a giraffe drinking water.

Diagram 1.1

Tilt the conical flask

(i) Based on diagram 1.2, how does a giraffe stand when it drinks water?

……………………………………………………………………..…………… [1 mark]

(ii) How does this way of standing give stability to the giraffe?

…………………………………………………………………………………..[1 mark]

(d) Give two ways to improve the stability of an object.

(i) ………………………………………………..…………………………………

(ii) …………………………………………………………………………………..[2 mark]

OBJECTIVE QUESTIONS

1.

The chair in the diagram above can be made more stable byA lengthening its legsB shortening its legsC changing the seat to a bigger oneD increasing the weight of the seat

2. The centre of gravity of an object can be lowered by A) Decreasing the height of the object B) Decreasing the base area of the object C) Making the object heavier at the top D) Making the object lighter at the centre.

3. Which of the following methods does not increase stability? A) Giraffes spread their legs wider B) Elephants have short legs C) An old man using a walking stick D) Giraffes have long necks

4. Which of the following shows the arrangement of animals in descending order ofstability?A Giraffe, gorilla, lion, crocodileB Crocodile, giraffe, gorilla, lionC Crocodile, gorilla, giraffe, lionD Crocodile, lion, gorilla, giraffe

5. A double-decker bus will be more stable if it I does not allow passengers to put heavy things at the lower deck II does not allow passengers to stand at the upper deck III fill the lower deck with passengers firstA I only B I and II only C II and III only D I, II, and III