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.
PRELIMINARY QUESTIONS
1. If you were to drop a ball, releasing it from rest, what information would be needed to predict how much time it would take for the ball to hit the floor? What assumptions must you make?
2. If the ball in Question 1 is traveling at a known horizontal velocity when it starts to fall, explain how you would calculate how far it will travel before it hits the ground.
3. A pair of computer-interfaced Photogates can be used to accurately measure the time interval for an object to break the beam of one Photogate and then another. If you wanted to know the velocity of the object, what additional information would you need?
ANALYSIS
1. Should you expect any numerical prediction based on experimental measurements to be exact? Would a range for the prediction be more appropriate? Explain.
2. Was your actual impact point between your minimum and maximum impact predictions? If so, your prediction was successful.
3. You accounted for variations in the velocity measurement in your range prediction. Are there other measurements you used which affect the range prediction? What are they?
4. Did you account for air resistance in your prediction? If so, how? If not, how would air resistance change the distance the ball flies?