The ball A of weight { W }_{ A } is thrown so that when it strikes the block B of weight { W }_{ B } it is traveling horizontally at speed v. Determine the average normal force exerted between A and B if the impact occurs in time Δt. The coefficient of restitution between A and B is e. Given: { W }_{ A } = 1 lb , { μ }_{ k } = 0.4 , { W }_{ B } = 10 lb , v = 20 ft/s , g = { 32.2ft/s }^{ 2 } , e = 0.6 , Δt = 0.02 s