Conservation Laws Assignment

Physics Experiment Report

Title: Conservation Laws

Hypothesis: Newton’s Third Law of motion states that for every action, there is an equal and opposite reaction. I expect to prove that once released, the ball(s) on one side of a Newton’s Cradle will strike the stationary ball(s) and create an equal and opposite reaction to the ball(s) other side.

Overview: To test Newton’s Third Law of motion, I will use a Newton’s Cradle simulator. I will release between one to four balls at a time to see if the corresponding number of balls are equally affected on the opposite side of the cradle.

Procedure:See Conservation Laws Instructions

Raw Data:See Conservation Laws Worksheet

Uncertainty & Error:

  • Using a computer simulation eliminates most errors. If programming errors existed which could introduce error, they should be eliminated while in the beta stage of programming, but the user would not likely notice minor errors if they still exist.
  • If the simulation were to be conducted in a physical environment with an actual working model of a Newton’s Cradle, the opportunity for error would be far greater, from such things as; having balls of differing weight/mass, strings of differing lengths, inconsistent striking surfaces of the balls, or the frame of the cradle bent or not symmetrically aligned. If any of these were true, the kinetic energy could be transferred outside the linear axis, causing the balls to exhibit reactions inconsistent with Newton’s Third Law.

Summary: For this experiment, I used a computer simulated model of a Newton’s Cradle to observe Newton’s third law of motion. I lifted between one to four balls and released them along their linear axis and observed what happened when they struck the stationary ball(s). I learned that when the ball(s) I released struck the stationary ball(s), the corresponding number of ball(s) on the opposite side of the Cradle were the only ball(s) that showed an effect, and when the ball(s) reached the apex of their swing, at approximately the same height which I had made the initial release, the process repeated itself, creating a back and forth pendulum-like motion. I also learned that changing the height at which I released the ball(s) resulted in a corresponding height in the reaction of the ball(s) on the opposite side of the cradle. This simulation was done with the use of a computer and though errors would be eliminated during testing, if incorrect formulas were programmed into the simulation which resulted in minor errors, those errors could easily be overlooked by most users. This experiment could be improved by inducing error and having the user observe the difference between a simulation with and without induced error.

Application: We can see how Newton’s Third Law can be seen in this experiment in other areas of our everyday lives. A couple of the things that come to mind which demonstrate this, would be; bumper cars at an amusement park, though the cars have braking systems to absorb the kinetic energy of being hit and Newton’s Third Law is harder to quantify. Another demonstration can be seen in the game of billiards, where a ball struck by the cue ball will shoot across the table and the cue ball can lose all of it’s kinetic energy by transferring it to the ball which it struck.