Computer 8A Physics with Vernier © Vernier Software & Technology 8A - 1 Projectile Motion 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. Figure 1 OBJECTIVES Measure the velocity of a ball using two Photogates. 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. MATERIALS computer plumb bob Vernier computer interface ramp and books Logger Pro 2 ring stands 2 Vernier Photogates 2 right-angle clamps ball (1 to 5 cm diameter) meter stick or metric measuring tape masking tape target Evaluation Copy
Computer 8A 8A - 2 Physics with Vernier PRELIMINARY QUESTIONS Balance one penny on the edge of a table. Place your index finger on a second penny, then flick the second penny so that it travels off the table, while the first penny is gently nudged off the edge. It may take a few practice trials to be able to do this effectively. Figure 2 1. Predict which penny will land first, the penny moving horizontally, or the one that simply drops off the table. Explain. 2. Perform the investigation, listening for the sound of the pennies as they land. Was your prediction supported or refuted? 3. You may believe the pennies landed just a little bit apart from each other. Try it a few more times. Does one always land before the other? 4. What will happen if you increase the speed of the second penny? Predict and then give it a try. 5. What if you increase the height from which the pennies are dropped? Your instructor may choose to stack two tables for you to test this.