Q2. (20 marks) A spherical virus particle is approximately 0.1 micrometre in diameter and its mass is approximately 11015kg. The virus particles often attach to respiratory droplets such as water droplets or aerosols (i.e. really small droplets) that are generated by breathing, talking, coughing, etc. The characteristic diameter of large droplets produced by sneezing is 100m, while the diameter of droplets produced by coughing is on the order of 1m. Answer the following questions (clearly state your assumptions): a) If a virus particle is attached to a water droplet with diameter 5m, estimate the time for the virus-laden water droplet to settle from a person's mouth (assume 1.7m above the ground) to ground. Clearly state your assumptions. (10 marks) b) If a virus particle is attached to a water droplet with diameter 500m, estimate the time for the virus-laden water droplet to settle from a person's month (assume 1.7m above the ground) to ground. (10 marks)