PEKA SAINS FORM 2

TOPIC: APPLICATION OF FRICTIONAL FORCE

Aim: To study the effects of different types of surfaces on the magnitude of fractional force

Problem statement: how does different type of surfaces affect the magnitude of frictional force?

Hypothesis: the rougher the surface, the greater is the magnitude of frictional force on the wooden block

Variable:

(a) Manipulated: type of surface(b) Responding: magnitude of frictional force(c) Controlled: size of the wooden block

Apparatus: spring balance, thread

Materials: wooden block, table, oil/grease, aluminium foil, sandpaper, graph paper

Diagram:

Procedure:

1. The apparatus is set-up as shown in the diagram above2. The wooden block is hooked to a spring balance with a

thread and place on the table3. The wooden block is pulled along the table and the

reading of the spring balance is taken when the block starts to move

4. Step 3 is repeated by pulling the wooden block on three other different types of surface

5. All the reading were recorded in the tableObservation:

Type of surface Condition of surface Reading of spring balance (N)

Wooden table rough 5.8 NAluminium foil smooth 4.5 N

Oil Very smooth 3.6 NSandpaper Very rough 6.5 N

Discussion:

1. Based on the collected data, draw a bar graph to show the effect of different types of surfaces on the magnitude of frictional force.

2. Between the different types of surfaces, which give thea. Greatest magnitude of frictional force?

The surface of sandpaper b. Lowest magnitude of frictional force?

The oily surface

3. What is the condition of the surface that causes thea. Increase of frictional force on the wooden block?

The rough surfaceb. Decrease the frictional force on the wooden block?

The smooth surface

4. Arrange in decreasing order the types of surfaces based on the magnitude of frictional force.Sandpaper, wooden table,aluminium foil, oil

5. Define operationally “frictional force”.Frictional force is the reading of spring balance when the wooden block is pulled on the surface

6. Based on the experiment, state the relationship between the frictional force and the types of surfaces.Frictional force depend on the types of surfaces

7. What is your inference from the results of the experimentThe reading of the spring balance is bigger because the contact surface is rougher

8. Suggest one way to decrease frictional force on the surface of the tableFriction on the table can be reduced by applying the grease on the surface of the table

Conclusion:

1. The rougher the surface, the greater is the magnitude of frictional force on the wooden block

2. The hypothesis is accepted.