You have probably watched a ball roll off a table and strike the floor. What determines where it will land? Could you predict where it will land? In this experiment, you will roll a ball down a ramp and determine the ball’s velocity with a pair of Photogates. You will use this information and your knowledge of physics to predict where the ball will land when it hits the floor.
* MEASURE THE VELOCITY OF A BALL USING TWO PHOTOGATES AND COMPUTER SOFTWARE FOR TIMING. * Apply concepts from two-dimensional kinematics to predict the impact point of a ball in projectile motion. * Take into account trial-to-trial variations in the velocity measurement when calculating the impact point.
|POWER MACINTOSH OR WINDOWS PC |PLUMB BOB | |LABPRO OR UNIVERSAL LAB INTERFACE |RAMP | |LOGGER PRO |TWO RING STANDS | |TWO VERNIER PHOTOGATES |TWO RIGHT-ANGLE CLAMPS | |BALL (1- TO 5-CM DIAMETER) |METER STICK OR METRIC MEASURING TAPE | |MASKING TAPE |TARGET |
1.SET UP A LOW RAMP MADE OF ANGLE MOLDING ON A TABLE SO THAT A BALL CAN ROLL DOWN THE RAMP, ACROSS A SHORT SECTION OF TABLE, AND OFF THE TABLE EDGE AS SHOWN IN FIGURE 1.
2.Position the Photogates so the ball rolls through each of the Photogates while rolling on the horizontal table surface (but not on the ramp). Approximately center the detection line of each Photogate on the middle of the ball. Connect Photogate 1 to the DG 1 of the ULI or DIG/SONIC 1 of the LabPro and Photogate 2 to the corresponding second port. To prevent accidental movement of the Photogates, use tape to secure the ringstands in place.
3.Mark a starting position on the ramp so that you can repeatedly roll the ball from the same place. Roll the ball down the ramp through each Photogate and off the table. Catch the ball as soon as it leaves the table. Note: Do not let the ball hit the floor during these trials or during the following velocity measurements. Make sure that the ball does not strike the sides of the Photogates. Reposition the Photogates if necessary.
4.Open the Experiment 8 file of Physics with Vernier (double check that it is called projectile motion). A data table and two graphs are displayed; one graph will show the time required for the ball to pass through the Photogates for each trial and the other will display the velocity of the object for each trial.
|5. You must enter the distance, s, between Photogates in order for Logger Pro to| | |calculate the velocity. The program will divide this distance by the time | | |interval t it measures to get the velocity (v = s/t). Carefully measure the |[pic] | |distance from the beam of Photogate 1 to the beam of Photogate 2. (It may be |Figure 2 | |easier to measure from the leading edge of Photogate 1 to the leading edge of | | |Photogate 2.) To successfully predict the impact point, you must enter an | | |accurate measurement. Enter the distance into Logger Pro by selecting Data |...