1. Tides approximate SHM Tides occur twice a day in New Zealand and the time between high and low tide is about 6 hours. A particular harbour has a 3 m tide. Ships entering the harbour may only do so when the tide is 2.5 m above the low water tide mark. reference circle 2.Calculate the time the Captain has, either side of the high tide, to get the ship safely into or out of the harbour. Low tide High tide 1.Neatly sketch the two diagrams below in your book. On your diagrams show a.the amplitude and period of the tides; b.the 2.5 m water mark above low tide; and c.the safe passage time for the ships to enter or leave the harbour. 1.Neatly sketch the two diagrams below in your book. On your diagrams show a.the amplitude and period of the tides; b.the 2.5 m water mark above low tide; and c.the safe passage time for the ships to enter or leave the harbour.

2. Tides occur twice a day in New Zealand and the time between high and low tide is about 6 hours. A particular harbour has a 3 m tide. Ships entering the harbour may only do so when the tide is 2.5 m above the low water tide mark. c.the safe passage time for the ships to enter or leave the harbour. reference circle Low tide High tide 2.5 m T = 12 hours A=1.5 m Time for safe passage r= A = 1.5 m a.the amplitude and period of the tides; b.the 2.5 m water mark above low tide; and Tides approximate SHM

3. reference circle Tides occur twice a day in New Zealand and the time between high and low tide is about 6 hours. A particular harbour has a 3 m tide. Ships entering the harbour may only do so when the tide is 2.5 m above the low water tide mark. 2.Calculate the time the Captain has, either side of the high tide, to get the ship safely into or out of the harbour. Low tide High tide Safe passage time 2.5 m T = 12 hours A=1.5 m 1.0 m r= A = 1.5 m 1.5 m 48 o  Tides approximate SHM

4. Tides occur twice a day in New Zealand and the time between high and low tide is about 6 hours. A particular harbour has a 3 m tide. Ships entering the harbour may only do so when the tide is 2.5 m above the low water tide mark. reference circle Low tide High tide 2.5 m T = 12 hours A=1.5 m Safe passage time 2.Calculate the time the Captain has, either side of the high tide, to get the ship safely into or out of the harbour. Captain has 1h 36m either side of high tide to enter or leave the harbour. 96 o 1.0 m 1.5 m 3 h 12 m Tides approximate SHM