Question

A boat is pulled into the dock by a rope attached to the bow of the boat and passing through a pulley on the dock that is 1 m higher than the bow of the boat.
If the rope is pulled in at a rate of 1.4 m/s, how fast is the boat approaching the dock when it is 9 m from the dock?

Answer 1

Answer:

√82/9 m/s

Explanation:

Let's say x²+1²= y²(y length of rope)

Using Pythagoras

With repect to t diff.

So 2x dx / dt= 2y dy / dt

But dy/ dt = 1.4m/s

X = 9 so from Pythagoras y = √82

So 9dx/dt = √82

So the boat will approved de dock at √82/9 m/s