A boat is pulled into a deck by means of a rope with one end attached to the bow of the boat and the other end passing through a ring attached to through the dock at a point 4 ft. higher than the bow of the boat. If the rope is pulled in at the rate of 2ft/sec, how fast is the boat approaching the dock when 10 ft. of rope is out??? plz help ;)

Question

A boat is pulled into a deck by means of a rope with one end attached to the bow of the boat and the other end passing through a ring attached to  through the dock at a point 4 ft. higher than the bow of the boat. If the rope is pulled in at the rate of 2ft/sec, how fast is the boat approaching the dock when 10 ft. of rope is out??? plz help ;)

anonymous · Answer

x²     +   y²  =   z²
100  + 16  =   z²   
=>         z    = 2√19
xx'       =  z z'
  x'       =  z z'/ x
            = 2√19 ( -2 ) / 10