During deceleration, acceleration anddeflection of a flowing fluid, there is a change of velocity and thus a changein momentum. Changes in momentum result in forces. In practice, the motiveforces are used to convert kinetic energy into work done, for example in aPelton turbine. In jet forces are generated and studied with the aid of a waterjet that acts on and is diverted by an interchangeable deflector. Theexperimental unit includes a transparent tank, a nozzle, four interchangeabledeflectors with different deflection angles and a weight-loaded scale. Theforce of the water jet is adjusted via the flow rate. Experiments study theinfluence of flow velocity and flow rate as well as of different deflectionangles. The jet forces generated by the water jet are measured on theweight-loaded scale. The forces are calculated using the momentum equation andcompared with the measurements.