   Steering force
  I'm reading "Programming game AI by Example" and i reach the part where it talks about how to create autonomously moving agents.To calculate the steering force the book propose to calculate the desired velocity and then subtract the current velocity. The thing is i cant understand how the subtraction of 2 velocities can be transform into a force.For me the subtraction of 2 velocities is equal to delta V  and also equal to acceleration*delta time.can somebody explain me why the subtraction of 2 velocities its equal to a force.   