A barge whose deck is 5 metres below the level of a dock is being drawn in by

means of a cable attached to the dock and passing through a ring on the dock.
When the barge is 12 metres away and approaching the dock at 3 4
metre per
minute, how fast is the cable being pulled in?

1 answer

Tan A = 5m/12m, A = 22.6o.

Cos22.6 = 3.4/V, V = 3.68 m/min.