Tsunami Alert!

An earthquake occurs 1200km from our coast. Instantly, a 5km deep column of water drops a few cm. This generates a tsunami, a tidal wave that moves at 500km/hr and is 2cm high.

Q1: The tsunami passes along the length of a 250m oil tanker. How long does it take to pass under the ship? Did they notice it?

Q2: The tsunami passes another ship 12 minutes later. How far is it between the ships?

Q3: The tsunami travels at the same speed until it reaches the edge of the continental shelf that lies 10km from shore. How long does it take the wave to reach this point?

Q4: As the tsunami traverses the continental shelf, it slows with uniform deceleration to a speed of 10m/s at the shore. What was the value of the deceleration?

Q5: Set time=0 as the tsunami first hits the shelf. How long does it take for the tsunami to cross the width of the continental shelf?

Q6: People on shore first notice the water receding and the wave building when it is 2km from shore. How long after the wave crosses the shelf edge is this? How long do they have before the tsunami crosses the shore?

Q7: If a tsunami warning system must give at least 10 minutes notice to those near the shore, and it takes 10 minutes to send out an alert, and 10 minutes to acquire and process data, how far off shore should ocean sensors be to give adequate warning time? (Treat the wave as travelling only at deep ocean speeds as an approximation.)