11a, lab 1: Motion, Measurement and Statistics
In the first lab we will investigate the motion of a ball rolling down an inclined plane. We will use this simple system to investigate the concept of systematic and random measurement uncertainties to understand how much we can trust a measurement. We will then compare the experimental outcome with theory.
I. Ball on an inclined plane: Measuring motion
We want to measure the motion of a ball that rolls down on an inclined plane and see whether this matches what we would expect. We will roll a ball down a tilted aluminum plate where gravity will accelerate the ball. It then rolls along a level surface (Plexiglas) where it should roll with approximately constant velocity as long as friction can be neglected.
• Set up the experiment. Start by placing the large wooden board onto the table, and use the adjustment screws and the level to ensure the plane is level. Place the Plexiglas strip onto the wood and use a steel ball to check again that it is indeed level.
• Place the ramp onto the metal inclines and use the magnets to secure it. Make sure the ramp touches the horizontal surface, but does not flex at …show more content…
If you want to get 100x better precision, you need 10,000x the number of measurements. In addition, there might be systematic errors that might for example depend on the person carrying out the measurement (reaction time) etc. Let’s explore a much more precise way of measuring velocity – photogates. We use two photogates that are connected to the computer. They consist of a little light emitting diode and a photo detector. If the spaced between the light emitter and the detector is blocked, an electronic signal is generated that is read out by the computer. The computer then measures the time difference between the arrival of the ball at the two
In the first lab we will investigate the motion of a ball rolling down an inclined plane. We will use this simple system to investigate the concept of systematic and random measurement uncertainties to understand how much we can trust a measurement. We will then compare the experimental outcome with theory.
I. Ball on an inclined plane: Measuring motion
We want to measure the motion of a ball that rolls down on an inclined plane and see whether this matches what we would expect. We will roll a ball down a tilted aluminum plate where gravity will accelerate the ball. It then rolls along a level surface (Plexiglas) where it should roll with approximately constant velocity as long as friction can be neglected.
• Set up the experiment. Start by placing the large wooden board onto the table, and use the adjustment screws and the level to ensure the plane is level. Place the Plexiglas strip onto the wood and use a steel ball to check again that it is indeed level.
• Place the ramp onto the metal inclines and use the magnets to secure it. Make sure the ramp touches the horizontal surface, but does not flex at …show more content…
If you want to get 100x better precision, you need 10,000x the number of measurements. In addition, there might be systematic errors that might for example depend on the person carrying out the measurement (reaction time) etc. Let’s explore a much more precise way of measuring velocity – photogates. We use two photogates that are connected to the computer. They consist of a little light emitting diode and a photo detector. If the spaced between the light emitter and the detector is blocked, an electronic signal is generated that is read out by the computer. The computer then measures the time difference between the arrival of the ball at the two