The harder you push, the more successful you are. What sounds so simple in theory is a bit more complicated in practice. Because even a muscleman will fail at “Hau den Lukas” if the technique isn’t right. “‘Hau den Lukas’ is a wonderful example of conservation of momentum in an elastic collision,” says Reinhard Kienberger, physics professor at the Technical University of Munich. During such a collision, two bodies collide without deforming or losing kinetic energy. Like with billiards, says Kienberger. There the momentum of the white ball is transferred to the hit ball with almost no loss.
The principle is the same with “Hau den Lukas”, except that the impulse of the hammer is passed on indirectly. The highlight: A seesaw is built into the base of the attraction. When the hammer hits the mandrel, its impulse is transferred to the rocker and thus to the loose bolt inside the device. This shoots upwards and, in the best case scenario, causes the bell to ring.
How far you can drive the bolt can be calculated if you know the mass of the hammer and bolt as well as the speed of the hammer. To do this, you have to divide the speed of the bolt (see graphic) squared by twice the acceleration due to gravity – which is 9.81 m/s² (s to the power of 2). According to Professor Kienberger, various factors are important in order to accelerate the hammer as effectively as possible. The size, body weight and muscle strength of the person hitting the ball would play a minor role. Much more important: the technology.
Professor Kienberger recommends taking advantage of the body’s possibilities. The hammer should be directly above the head. Hold it at the upper end with your leading hand and let it slide to the lower end of the handle during the striking movement to the weaker hand. This increases the turning radius and speed.
During the punch you should also use the natural rotational movement of the shoulders and hips, which allows you to better incorporate the mass of your body into the impulse. You should also hit the mandrel as parallel as possible, otherwise the edge of the hammer will end up on the table or the mandrel will get wedged. The best thing to do before striking is to test where you stand and how far you have to bend your knees to hit the spike perfectly.
In the series “The Physics of the Oktoberfest” the SZ analyzes various components of the Oktoberfest according to scientific criteria.
Good Oktoberfest stories stay good. This text was first published on September 28th published.