- In a harbour, the water level rises and falls with the tides with simple harmonic motion.
On a particular day, the depths of water in the harbour at low and high tide are 4 m and 10 m respectively.
Low tide occurs at 12:00 and high tide occurs at 18:20
- Find, in \(\mathrm { mh } ^ { - 1 }\), the speed at which the water level is rising on this particular day at 13:35
A ship can only safely enter the harbour when the depth of water is at least 8.5 m .
- Find the earliest time after 12:00 on this particular day at which it is safe for the ship to enter the harbour, giving your answer to the nearest minute.