In setting its anchor in 100 ft of water, a small power boat reverses its propeller, which...

In setting its anchor in 100 ft of water, a small power boat reverses its propeller, which gives a reverse thrust P = 800 lb. A total of 400 ft of anchor chain from anchor to bow has been released. The chain weighs 1.63 lb/ft, and the upward force due to water buoyancy is 0.21 lb/ft. Calculate the length l of chain in contact with the bottom.