A hollow aluminium sphere has an external radius of 10cm and a uniform thickness of 1cm. The density of aluminium is 2700kgm−3. The sphere is gently placed in fresh water (density 1000kgm−3).
(i) Calculate the mass of aluminium used in making the sphere.
(ii) Determine the average density of the hollow sphere.
(iii) State whether the sphere will float or sink in water, giving a reason based on your calculation.
(iv) If it floats, calculate the percentage of the sphere’s volume that will remain above the water surface.