I Bmt – Revision Grade Ix 1. Define The Following

I BMT – REVISION GRADE IX 1. Define the following quantities, give their formulae and units (i) speed (ii) velocity (iii) acceleration 2. Differentiate between a scalar and a vector quantity and give one example for each. 3. Give the formulae for force and weight. (i) F = _______________________ (ii) W = ______________________ 4. Draw speed time graphs for (i) Body at rest (ii) Body with constant velocity (acceleration = 0) (iii) Body with constant acceleration (iv) Body with variable acceleration (v) Body with constant deceleration 5. From a speed time graph how would you determine (i) the distance (ii) the acceleration or deceleration 6. Plot the following data in a graph sheet and then answer the questions that follow: Speed,

0

5

10

15

20

25

25

25

25

m/s Time , s 0 1 2 3 4 5 6 7 8 (i) State the time during with the body is traveling with constant speed

25

25

20

10

0

9

10

11

12

13

(ii) Describe the motion of the body from 0 to 5 seconds and from 10 to 13 seconds. (iii) Calculate the acceleration of the body in the first 4 seconds (iv) Calculate the deceleration of the body in the last 2 seconds. (v) Calculate the total distance traveled by the body. (vi) Calculate the average speed of the body during your motion. (vii) If this body were to travel with the same speeds around a circular track, state one similarity in its motion during 6 second and 10 second. (viii) What is the resultant force which acts to keep this body in the circular path called as? In which direction is this force acting?

7.

ExtensionV sLoad 80

70

extension /cm

60

50

40

30

20

10

0 0

5

10

15

Load/N

(i) Calculate the spring constant for this graph. (ii) Mark with a point (X) and show on the graph the elastic limit of the graph. (iii) When the load is about 10N, the spring does not obey Hooke’s law. What does this mean?

8.

(i) The diagram shows a metre rule balanced about its centre. (ii) What does the term ‘balanced’ mean? (iii) A 3 kg mass and a 2 kg mass are hung on either side of the rule so that the rule remains horizontal. Calculate the force caused by each mass. (iv) Mark on the diagram to qualitatively show the positions of the two masses so that the rule remains in equilibrium. (v) In another experiment a metre rule was found to balance on its 49 cm mark due to a manufacturer’s defect. A 30 N load is hung from 59 cm mark. Calculate using the law of moments where a 20 N load should be hung from the rule so that the rule is balanced. 9.

(i) Name the three states of equilibrium the Bunsen burner is in. (ii)

The burner shown above is stable. Show by marking the location of the centre of mass of this object. (iii) What are the conditions for an object to be stable? (iv) Why would it be wrong to open the top drawer in this chest of drawers?

(v)How would you improve the stability of this object? (vi) A boy stuffs all his clothes in the top drawer. How would this affect the stability of this object? 10. 800N

600N

35o 90o

Draw a suitable scale diagram to find the resultant of these two forces.

11. The following diagram shows the results obtained in an experiment to find the density of a stone. (i) From the data given, calculate the density of the stone. (ii) State three precautions to be taken while performing this experiment.