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During a heavy rain, hailstones of average size 1.0 cm in diameter fall with an average speed of 20 m/s. Suppose 2000 hailstones strike every square meter of a 10m x 10m roof perpendicularly in one second and assume that the hailstones do not rebound. Calculate the average force exerted by the falling hailstones on the roof. Density of a hailstone is 900 kg/m³. |
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Answer» Thanks for asking the QUESTION! ANSWER:: Diameter of hailstone , d = 1.0 cm v = 20 m/s u = 0 ρ = 900 kg/m³ = 0.9 gm/cm³ Volume of hailstone = (4/3)πr³ = (4/3)π(0.5)³ = 0.5238 cm³ Mass of hailstone = vρ = 0.5238 x 0.9 = 0.4714258 gm Mass of 2000 hailstone = 2000 x 0.4714258 = 942.8516 Rate of change in MOMENTUM per unit area = 942.8516 x 2000 = 1885703.2 =18.85 kg m/s² = 18.85 N Total force on roof = 18.85 x 10 x 10 = 1885 N ≈ 1900 N Hope it helps! |
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