A bucket is full of oil. The total mass of the bucket of oil is 5.4 kg and the gravitational field strength is 10 N/kg.

a. Calculate the total weight of the bucket of oil.

b. The bucket of oil is hung from a spring of unstretched length 20 cm. The limit of proportionality of the spring is not exceeded and its length increases to 35 cm.

i. State what is meant by the limit of proportionality.

ii. The oil is poured into a measuring tank. The empty bucket stretches the spring to a length of 25 cm. Calculate

1 The force that stretches the spring to a length of 25 cm.

2. The mass of the oil in the measuring tank.

iii. The volume of the oil in the measuring tank is 0.0045 m³. Calculate the density of the oil.

c. Explain, in terms of their molecules, why the density of the oil is greater than that of air.