Question

A ferry is travelling at 10 m/s relative to the river towards the south. The river is flowing at 2 m/s relative to

the riverbank towards the south. If a passenger on the ferry walks towards the rear of the ferry (north) at 1.0
m/s, what is their velocity relative to the riverbank?

Answer 1

11 m/s south

Step-by-step explanation:

The velocity of the passenger relative to the river bank is equal to the velocity of the passenger relative to the ferry, plus the velocity of the ferry relative to the river, plus the velocity of the river relative to the river bank.

v_passenger,bank = v_passenger,ferry + v_ferry,river + v_river,bank

If we take north to be positive and south to be negative:

v = 1.0 m/s + (-10 m/s) + (-2 m/s)

v = -11 m/s

v = 11 m/s south