Hello I'll make it quick Boat is travelling at 10m/s the sea is travelling at 5m/s. What is the speed of the boat relative to the sea and why? Through vectors I worked it out to be 10m/s(not sure) but shouldn't it be five because if a person is standing in the sea and sees the boat it would be travelling at 5m/s. The ship relative to the ground is 15m/s right. Thank you!!