PHYSICS PEKA FORM 4: MASS AND INERTIA

Inference: The period of the oscillation is depends on the mass of plasticine

Hypothesis: The bigger the mass the longer the period of the oscillation

Aim: To investigate the relationship between the inertia of the object and its mass

Variables:

1) Manipulated variable: Mass of the plasticine , m

2) Responding variable: Period of the oscillation, T

3) Fixed variable: The stiffness of jigsaw blade and

the distance of the centre of the plasticine from

the clamp

Apparatus and materials: Jigsaw blade , stopwatch , plasticine sphere of different masses and G-clamp

1) Apparatus and materials are setup as shown in the diagram.

2) A 20g plasticine ball is fixed at the free end of the blade.

3) The free end of the blade is displaced horizontally and released so that it oscillates. The time for 10 complete oscillations,t1is measured using a stopwatch and recorded.

Procedure:

4) Step (3) is repeated to get t2. The average

of 10 complete oscillations, t is calculated. Then the period of oscillation is determined ,T

5) Step (3) and step (4) are repeated using plasticine ball with masses 40g , 60g , 80g and 100g

6) A graph of T2 versus mass of load, m is drawn

The change in mass and time for 10 oscillations are recorded in the table below:

Results:

Mass of plasticine, m

(g)

Time for 10 oscillations, t

(s)

Period, T (s) Square period, T2 (s2)

t1 t2 t

20.0

40.0

60.0

80.0

100.0

1) From the experiment it is observed that the bigger the mass of plasticine attached to the jigsaw blade, the bigger the period of oscillation of the blade.

2) The period of the oscillation is an indicator of inertia of the plasticine whereby the bigger the period of oscillation , the bigger is the inertia of the plasticine. Hence , the bigger is the mass of the plasticine , the bigger is its inertia

Discussion

The gradient of the graph:

From the graph:When a) The mass of plasticine = 12 g

Period of oscillation= …………….

m

Tm

2

gs /............. 2

b) The mass of plasticine = 22 g Period of oscillation= …………….

c) The mass of plasticine = 52 g Period of oscillation= …………….

Conclusion:Object with a larger mass has larger inertia

Precautions:1) The jigsaw blade must be horizontal.2) Make sure the plasticine ball is oscillating

in the same horizontal plane