2010 PMR Science Paper 2 (Continuation)

8.  Diagram 8.1 shows the same student lifting two bags of different masses onto a table.

(a) Based on the observation in Diagram 8.1:

(i) Compare the difference in work done between situation L and situation M.

     Work done in situation L is less than in situation M

(ii) State one relationship between the mass of the bag and the time taken to lift it.

     The heavier the bag, the more the time taken to lift the bag

(iii) Write one inference about the bag in situation L.

     Bag in L is lighter because the time taken to lift it is shorter

(b) A student lifts up three weights of different values from the floor onto a table using a spring balance.  Diagram 8.2 shows three readings of the spring balance in P, Q and R.

      Table 8 shows the readings of the spring balance in P, Q and R.

Spring balance	Mass of weight (kg)	Reading of spring balance (N)
P	10	100
Q	15	150
R	20	200

                                                             Table 8

(i) Based on Diagram 8.3, state the reading of the spring balance.       250N

(ii) Based on the data in Table 8, draw a line graph of the readings of the spring balance against the mass of the weight.

Transfer all points correctly : 1 mark
Joint all correct points smoothly : 1 mark
(iv) State the variable involved in this activity.

Responding variable	Reading of spring balance
Manipulated variable	Mass of weight

(c) (i) State the operational definition of work done in Diagram 8.1.

         Work done is the time taken to lift the bag

(ii)  Diagram 8.4 shows four everyday activities, S, T, U and W.

Based on the operational definition of work done in 8(c)(i), classify the activities in Diagram 8.4 based on work done.

Classification	Activities
Work done	S, U
No work done	T, W

                                      *********The End*********

2010 PMR Science Paper 2 (Continuation)

7.  Diagram 7 shows the apparatus set-up to study the fractional distillation of petroleum.

(a) (i) Based on the observation in Diagram 7, record the readings of thermometer in L and N into Table 7.1.

Reading of thermometer	Temperature (oC)
L	36
M	52
N	88

(ii) Compare the colour of the distillate in fraction 2 and fraction 3.

    The colour of the distillate in fraction 2 is lighter than in fraction 3.

(iii) State one hypothesis that can be made from this study.

     The higher the temperature, the darker the colour of the distillate.

(b) State the variables involved in this study.

Manipulated variable	Temperature
Responding variable	Distillate colour

 

(c) Table 7 .2 shows the result of this study.

(i) Based on the result in Table 7 .2, state one inference about the soot produced during the burning of the distillate.

    As the temperature/boiling point increases, more soot is produced because the fraction is less combustible.

(ii) Predict the colour of the distillate if the temperature is more than 200^oC.

     Darker than yellow//dark yellow //brown

2010 PMR Science Paper 2 (Continuation)

5 (a) Diagram 5.1 shows two syringes, P and Q, before and after compression. Syringe P is filled with substance L and syringe Q is filled with substance M.

    (i) Write the state of matter of substance M.     Gas

    (ii) State one step to increase the pressure in syringe Q.

         Push the piston // Decrease the volume

   (iii) Compare the arrangement of particles of substance L and substance M.

         The arrangement of particles in substance M are further apart than the particles in substance L.

 

    (b) Diagram 5.2 shows a student sucking water using a straw.

          Based on the principle of air pressure, state why this student is able to suck the water.

          Pressure inside the straw is lower than outside the straw // Pressure outside the straw is higher than inside the straw

     

     (c) Diagram 5.3 shows a plunger used to clear a blocked pipe.

          (i) Compare the air pressure at K and the air pressure at L.

               Pressure at K is higher than at L

          (ii) State how to use a plunger to clear the blocked pipe.

               Push and pull // press and pull // pump and pull 

         (iii) Give one reason for the answer in 5(c)(ii).

               When the plunger is pushed/pulled, the air pressure under the rubber sucker is

       reduced/ lowered/ decreased

6. The following are steps in an investigation to study the transport system in a plant.

     (a) Why is the exposed ringed area wiped with paraffin?

         To prevent it from drying /dehydrating // prevent from infection             

     (b) Diagram 6.2 shows the exposed ringed area before and after three weeks.

      (i)  What happens to the upper part of the exposed ringed area after three weeks?

            Swollen // bigger

     (ii)  Give one reason for the answer in 6(b)(i).

           Food/glucose cannot get into tissue below the ring // food is accumulated.

     (iii) What is the function of phloem?

           Transport food/glucose

     (c) Diagram 6.3 shows the exposed ringed area covered with soil instead of paraffin. After a few months, the roots grow. This is one method of reproduction.

      (i) State the type of this reproduction.

          Asexual /vegetative reproduction

     (ii) Give one advantage of the reproduction stated in 6(c)(i).

          Produces plant/offspring faster // maintains good quality of the parent// matures faster // saves cost 

     (d) Diagram 6.4 shows a piece of wire tied tightly around a tree trunk. This has a negative effect on the growth of the tree after many years.

      (i) Suggest one way to avoid the negative effect on the growth of this tree.

          Put / place wood/cloth/tyre in between wire and tree trunk

     (ii) Give one reason for the answer in 6(d)(i).

          Phloem will not be damaged// Food can be transported to the bottom of plant
          To be continued..........