Simple harmonic motion rise and fall of water

[thereddevils]

Homework Statement

The rise and fall of water in a harbour is simple harmonic. The depth of water varies between 5.0 m at low tide and 9.0 m at high tide. The time between sucessive low tides is 12 hours. A ship, which requires a minimum depth of 6.0 m approaches the harbour at low tide, how long the ship has to wait before entering the harbour?

Homework Equations

The Attempt at a Solution

A hint to start?

 

[Shivpal]

The time period of oscillations is given to you as 12hrs, the amplitude is (9-5)/2 = 2 meters, now for the tide to be at least 6m (minimum need for ship to pass), your oscillator must be 1m away from the lowest position moving toward the center.

 

[thereddevils]

The time period of oscillations is given to you as 12hrs, the amplitude is (9-5)/2 = 2 meters, now for the tide to be at least 6m (minimum need for ship to pass), your oscillator must be 1m away from the lowest position moving toward the center.

Thanks Shivpal, but i don get the meaning of this sentence.

'your oscillator must be 1m away from the lowest position moving toward the center.'

 

[thereddevils]

Thanks Shivpal, but i don get the meaning of this sentence.

'your oscillator must be 1m away from the lowest position moving toward the center.'

Never mind, i got it.