During a heavy rain hailstones of average size 1 cm dia falls with a average speed of 20 m/s. Suppose 200 hailstones strike every sq.m of a 10mX10m roof perpendicularly in one sec 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 900kg/cu.m
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2 Answers
62initial momentum of each hailstone is mv=[\rho V]v=900\times\frac{4\pi r^3}{3}v=900\times\frac{4\pi (10^{-2})^3}{3}\times 20 =.024\pi
Momentum of the hailstones falling in one second on 10x10 m roof is .....024\pi\times200\times100
which is the change of momentum per unit time.. which is the average force on the roof
1suppose mass of 1 is m.dn frce exerted by one is mg+mv(change in momentum per sec).ds is frce on floor by 1 hailstone.multiply it by no. of hailstone strking d surface per sec