PHYSICS III

ST. MARTIN’S GIRL’S SCHOOL, KIBAGARE
P.O.BOX 14960-00800
FORM 4 PHYSICS ASSINEMENT III, FRIDAY 11TH SEPTEMBER 2009
NAME:____________________________________________________________--

1. State the law of floatation. 1MK

a) A balloon of negligible weight and capacity 50m3 is filled with helium of density 0.18kgm-3. Calculate the lifting force of the balloon if the density of air is 1.2kgm-3. 3MK


b) Draw a well labeled diagram of a common hydrometer capable of measuring the density of liquid in the range 1.0 to 0.7gm-3 2MK





c) State the use of such a hydrometer. 1MK

2. State the kinetic theory of matter. 1MK


3. State one way in which vehicle assembling companies enhance the stability of vehicles. 1MK

4. Water at a speed of 1ms-1 is pumped through a loose pipe of diameter 2cm to a sprinkler having 30 holes each of diameter 2mm. What will be the speed of delivery of the water at the sprinkles? 3MK



5. State one basic laboratory rule that a student working in a physics laboratory should observe.1MK

6. Explain why a drop of methylated spirit placed at the back of the hand feels colder than a drop of water although they are at the same temperature? 2MK



7. The tape attached to a moving trolley is run through a ticker tape time with the vibrator switched on. Figure 1 shows a section of the tape after running.


Figure 1



8. If the frequency of the ticker timer is 50Hz, determine the acceleration of the trolley. 4mks