Question

How do you work out relative velocity?

Answer 1

How you work out relative velocity will depend on the speeds you are interested in.
If the speeds are small, you can use simple addition and subtraction.
If boat 1 moves with velocity a=2 and boat 2 moves with velocity b=3, the velocity of boat 1 according to boat 2 is (a-b= -1) and the velocity of boat 2 according to boat 1 is (b-a= 1).

What you are really doing is taking one boat as if it is standing still and determining how fast the other boat is moving according to the first boatt.

Answer 2

Absolute velocity is the actual velocity of an object. However, the velocity of the object seems to be different from another frame of reference which is itself mobile. In order to find the relative velocity from another reference frame, we consider the mobile frame to be at rest and add/subtract its velocity from the object to obtain the relative velocity.
The absolute velocity is always the same for an object but the relative velocity is different for every frame of reference .

Answer 3

forget all stuff u wanna learn about relative velo. let's say there are n things moving
what u do simply grab one of 'em and think in mind how other things will appear to u

Answer 4

You must have sat in a car on a two-lane road. If you are driving along at 50 mph and a car overtakes you at 60 mph, it is going away from you at 10mph. Your absolute velocity is 50; the other car's is 60; and their velocity relative to you is 10.