Bordtennisboldens hoppetid: analyse af faldlov og energier

Indholdsfortegnelse

Abstrakts. 3

Indlednings. 4

Forsøgs. 5

Databeregnings. 7

Fejlkilders. 11

Diskussions. 11

Konklusions. 11

Litteraturlistes. 12

Bilag 1s. 13

Bilag 2s. 14

Bilag 3s. 15

Abstract

The objective is to find the time it takes a table tennis ball to stop hopping from having being released from a certain height. An experiment was made. A table tennis ball was released from about 1m height. The action of the ball was videotaped and imported to the computer program “Tracker”. The results were used and made a graph that beautifully showed the balls movements. The results from the experiment were in seconds and meters. Since it was the time we wanted to find. Using the number e (when the ball hits the floor) and the knowledge of energy terms and Galilei’s law about falling objects it is possible to find the total time it takes the ball to stop hopping.

The final formula is:

Which means that from a release height on 1,153m it takes the ball 20,50 seconds before it has stopped hopping, in theory of course.

Indledning

Jeg vil i denne opgave beskæftige mig med Galileis faldlov og energier. Når en bold slippes fra en højde ændres dens potentielle energi til kinetisk efterhånden som den nærmer sig nulniveauet. Den afgiver noget energi når den rammer jorden og hopper videre med en ny hastighed op til en ny højde. Derfor ændres tiden det tager for bolden og at falde til nulniveauet for hver nyt hop, altså hver ny højde. Jeg vil finde den samlede tid det tager fra bolden slippes til den ikke hopper mere. For at finde denne, laves to forsøg, hvor det ene bruges til databeregning og det anden til direkte måling af den totale tid. De to resultater vil jeg til slut sammenligne og konkludere på.