A method of simulating a dynamic force event comprises rotating a cam about an axis according to a rotational speed profile and biasing a follower against a surface of the cam as the cam rotates so that the follower moves on the surface and imparts a braking force against the surface. The method further measures the braking force on the rotating cam with a measurement device operatively connected to the cam, the braking force varying according to the friction between the cam surface and follower moving against one another. In another aspect of the invention, a method of calibrating a testing machine measures a braking force resisting movement of a first body over time to produce a simulated dynamic force response of the first body and compares it with a standard dynamic force response to calibrate the testing machine.