According to Bernoulli's law pressure and velocity along a stream line are related to each other. What is the most correct way to describe it ? A. First the pressure change and then the flow velocity change. the change in the flow velocity is caused by the pressure change (F=Ma> PA=Ma). B. First the velocity change and then it cause change in pressure (for example: flow throw a nozzle). I'm not sure about B., because if the velocity change there must be some force who causes it - F=Ma , and if this force is not related to pressure, what other force can it be? And I'm not sure about A., because what causes the change in pressure if not the velocity change?