Final answer:
Pressure is the sum of forces on an athlete or object that are applied perpendicular to the direction of flow.
Step-by-step explanation:
Pressure is the sum of forces on an athlete or object that are applied perpendicular to the direction of flow. This can be seen in examples such as the pressure inside a tire or the pressure exerted on a swimmer by water. In both cases, the forces exerted are perpendicular to the surfaces they contact.