Principle
Before the start, both cars are at rest and the individual impulses of the cars and the total impulse of the car system are Zero. The potential energy stored in the detonator sets the cars in motion when they start. In accordance with the pulse conservation law, however, the sum of the signed individual pulses remains zero even after the start; the speed of the carriages and the car masses used also result from the pulse conservation law.
Benefits
- Especially understandable and didactically prepared description of the experiment (relevance to everyday life, etc.) including protocol questions.
- Future-oriented teaching: Integration into digital science lessons with tablets or smartphones.
- Increased motivation of students by using the intuitive measureAPP.
- Increased media competence.
Tasks
- The students connect two stationary cars of the same mass with an explosion starter (spring with suction cup),
so that the cars start up suddenly. Both cars drive through a light barrier, which determines the respective shading time
measures from which the driving speed is determined. - The students increase the masses of both cars equally and repeat the measurements.
- The students now reduce the mass of one of the carriages so that one carriage is now heavier than the other and
carry out the experiment again.
Learning Objectives
In this experiment, the students are to be introduced to the quantity of momentum as a fundamental conservation variable and to develop a get a first impression of the usefulness of the conservation variable for calculations. It should also be indicated that the momentum, like the velocity, has a direction (vectorial quantity) - in contrast to quantity-like (scalar) quantities such as mass.