Comet Halley is an irregularly-shaped comet which is visible from Earth every 75-76 years. For the purposes of this question, we will assume that the comet is spherical. a) Taking the diameter of the comet to be 10.6km, find the approximate volume of the comet in cubic centimetres. You may use the fact that the volume of a sphere is 4 V=3r where r is the radius. b) The density of (water) ice is one gram per cubic centimetre. It is estimated that the density of the comet is approximately the same as that of water ice. Given that mass = volume x density find the mass of the comet in kilograms. Hint: Find the mass in grams first and then convert.