How long does the ripple take to reach the boat?

Question

A rock is dropped into a pond, creating a circular ripple. The radius of the ripple increases steadily at 6cm/s. A toy boat is floating on the pond, 2.00m east and 1.00m north of the spot where the rock is dropped. How long does the ripple take to reach the boat?

Answer 1

Divide the distance r from the spot to the boat by the speed v of the ripple.

 

t = d/v

 

v = 0.06 m/s

 

d = √(2.00² + 1.00²) m = ? m

 

Plug in the numbers and get t in seconds.