M3.1 Laboratory Report 3

PHY2053L 9/17/2023 M3.1 Laboratory Report 3: Projectile Motion Purpose:

The purpose of this experiment is to explore the principles of projectile motion using the simulation. Specifically, to understand the factors that influence the motion of objects shot through the air and to analyze the effect of changing variables such as initial speed, angle of launch, and the choice of projectile. Introduction: In this experiment, I will utilize the PhET Simulation to delve into the concept of projectile motion. Projectile motion involves the motion of an object that is projected into the air, such as an arrow from a crossbow or a cannonball from a cannon. This type of motion is influenced by various factors, including the initial speed, launch angle, and the effects of gravity. Procedure: Part I: Lab Option: 1. Open the Lab option in your simulator 2. Increase the height of the platform where the cannon is placed to 8 m. 3. From the drop-down menu choose Pumpkin and set the angle to 0- degree loft. 4. Set the initial speed to 2 m/s and shoot the Pumpkin. 5. Use the crosshairs marked with time range and height to mark the last dot of the flight. 6. Fill in the table below with the values. 7. Next, set the initial speed to 4 m/s, without changing the height or the angle, and repeat steps 5-6. 8. Keep changing the initial speed by increment of 2 m/s until you obtain 10 measurements, extend, and fill in the table 9. What do these values tell you? 10. Change to a different projectile like a car and repeat the same steps (1-8). What do the results tell you? Part II: Vectors a.

1. Use the same set up and investigate the effect of mass, different object shot, gravity, diameter, altitude, air resistance and drag coefficient 2. Include your observations and investigation in the conclusion section of your lab report. Part II: Acceleration due to Gravity Determination: 1. Choose the Lab option in your simulator. 2. Uncheck the “air resistance box”. 3. Set the following: initial speed = 16 m/s and the cannon angle = 54º. 4. Use the crosshair tool and measure the maximum height, the range, and the time in flight. 5. Use the kinematics equations to calculate with these given the acceleration due to gravity. 6. Compare your calculated value to the accepted value for g = 9.80 m/s 2 (Calculate your percent error). Data and Data Evaluation: Part I: Lab Option Table : Initial Speed (m/s) Time (s) Range (m) Height (m) 2 1.28 2.55 0 4 1.28 5.11 0 6 1.28 7.66 0 8 1.28 10.22 0 10 1.28 12.77 0 12 1.28 15.33 0 14 1.28 17.88 0 16 1.28 20.43 0 18 1.28 22.99 0 20 1.28 25.54 0 Picture 1:

Part II: Vectors a. Initial Setup and Investigating Gravitational Acceleration Picture 2: b. Initial Setup and Investigating Velocity

Results and Conclusion: Part I: Lab Option The data in the table indicate that air resistance has an influence on the time and height of the projectile when changing its speed. Without air resistance, the projectile’s time or height will not be impacted, only the range. Part II: Vectors a. The vector is pointing downwards while the projectile is accelerating in the direction indicated by this vector. Throughout its flight, the vector's length stays constant, which indicates that the vector's magnitude won't vary and that it will continue to point downward during the flight. Since the cannonball will experience the same force of gravity regardless of the cannon's angle, I don’t believe that the acceleration vector will vary if the cannon's angle changes. The acceleration vector stayed constant in length and showed no signs of change. b. As the cannonball goes up, it slows down and points upwards ( y ) due to gravity opposing its upward movement. At its highest point, it stops moving up briefly (velocity vector in the upward direction becomes zero). Then, as it comes down, the velocity points downwards and increases due to gravity

allowing it to fall faster. The velocity in the horizontal ( x ) direction doesn’t change because gravity doesn’t affect it. It stays the same throughout the whole flight. c. When there is no air resistance, all objects will travel the same range, height, and time while the variables are constant. However, the height and range of the object are decreased when air resistance exists, but the amount of time is unaffected. The object will travel farther, faster, and lower in height if the force of gravity is increased. The time, range, and height of the object’s flight will all be slightly reduced if the height is increased, on the other hand. The object’s size has no effect on its time, range, or height. The results from the simulation were almost identical to the calculated results. In Part II: Acceleration due to Gravity Determination, the calculated result that I obtained was 9.81 m/s 2 , which was very close to the accepted value for g = 9.80 m/s 2 . The percent error was 0.102 m/s 2 , which indicates that it was very close to the accepted value. In this experiment, I investigated various aspects of projectile motion using the PhET simulation. I observed that changing the initial speed and launch angle significantly affected the time of flight, range, and height of the projectile. The data collected demonstrated the relationship between these variables and the motion of the object.