Home » Maths for Planet Earth » A Speedy Sea Current

A Speedy Sea Current


An ocean current separates into 2 different currents at a small island that can be modelled as the origin. Current A heads due south and current B heads on a bearing of 100˚. 

An oceanographer wants to measure the relative surface speeds of these two separate currents, by placing buoys in them off the island and measuring the distance travelled by the buoy in 20 hours.

After 20 hours, the buoy in current A has travelled 150km whilst the buoy in current B has travelled 250km.

 Find the average speeds of the two ocean currents.

[2 marks]

b) Calculate the final distance between the buoys.

[2 marks]

c) Θ is the final bearing of the buoy in current B from the buoy in current A. Show that \(\frac{\sin\theta}{\sin{80}} = 0.93\) to 2 decimal places.

[3 marks]

d) Find the area of the triangle with the island and the two buoys as its

[3 marks]

Start exploring

Latest from blog

More Maths for Planet Earth

A Level
A country’s government wants to reduce the number of cars using internal combustion engines by encouraging the purchase of electric vehicles. The total number
A Level
A country decides to subsidise the purchase of electric vehicles, causing more people to buy them. Initially, the country used an equivalent of 56
A Level
3 CO₂ monitors K, L and M are placed on a mountain side The vector (overrightarrow{text{KL}} = 3mathbf{i -}6mathbf{k}) and (overrightarrow{text{LM}} = 2mathbf{i} +
The graph shows satellite measurements of global sea level rise since 2000 plotted relative to 1993. (sea level rise measured in mm = millimetres)