I cannot know how to calculate the force of the hail During a violent thunderstorm, hail the size of marbles (diameter = 1.20 cm) falls at a speed of 14.0 m/s. There are estimated to be 110.0 hailstones per cubic meter of air. Assume that, as for ice, 1.00 cm3 of hail has a mass of 0.920 g. What is the mass of each hailstone? What is the magnitude of the force exerted by the hail on a 9.0 m x 20.0 m flat roof during the storm ? Ignore the bounce of the hail on impact. please help me, Thanks in advance.