PHY 101L Module Three Lab Report Projectile Motion

PHY 101L Module Three Lab Report Projectile Motion Name: Clay Wagner Date: 11/11/16 Complete this lab report by replacing the bracketed text with the relevant information. Activity 1: Horizontal Projectile Motion Data Table Activity 1 Table 1 Trial Sphere θ a = 0.71(9.8)sinθ ? 𝒙 = √(2 𝒂? ) 𝑡 = √(2 ℎ / ? ) Calculated Distance 𝑥 = ? 𝒙 𝑡 Actual Distance Percent Difference 1 Steel 15 1.8 16.4 3.9 0.64 m 0.42 m 34.4% 2 Steel +5° 2.4 18.9 3.9 0.74 m 0.53m 38.4% 3 Steel +10° 2.9 20.9 3.9 0.82 m 0.66m 19.5% 4 Acrylic 15 1.8 16.4 3.9 0.64 m 0.36 m 43.8% 5 Acrylic +5° 2.4 18.9 3.9 0.74 m 0.45 m 39.2% 6 Acrylic +10° 2.9 20.9 3.9 0.82 m 0.51m 37.8% Activity 1: Questions 1. Did the sphere in the experiment always land exactly where predicted? If not, why was there a difference between the distance calculated and the distance measured? The spheres landed at different distances than the calculated ones. This is because air resistance is not included in the calculations. Friction from the ruler also effects the spheres range, and there is no friction in the equations. 2. Why is it important to use the grooved ruler to ensure that the sphere leaves the table in a horizontal direction? To make sure that the sphere moves only in a horizontal direction. Without the groove the ball is more likely to stray off path and alter the measurement. The ruler keeps the ball in 2D motion, while without it, the sphere would move into 3D motion. 3. If the same experiment were performed on the moon, what would be different? Since the gravity is lower on the moon, the time for the motion would be greater than on earth. The acceleration, velocity, and distance would all be affected. 4. What is different about the vertical component of the sphere’s velocity and the horizontal component of the sphere’s velocity once the sphere leaves the table? The vertical component of the sphere’s velocity is under constant acceleration due to gravity. The horizontal is not subject to any external forces and should be constant (theoretically). 5. If the same experiment were repeated with the same angles, but from a taller table, how would the results change? The time will increase at a higher table. The acceleration will increase, because the acceleration of the spheres is dependent upon the height of the table. This will increase the distance traveled by the spheres and their velocity.

Activity 2: Exploring Projectile Motion with a Simulation In this activity, you will explore how altering the variables of the initial launch condition of a projectile affects the projectile’s trajectory. Adobe Flash is required for the PhET projectile motion simulator website. The simulation will allow you to change the following variables: Angle : This is the angle between the launch vector and the horizontal. Initial Speed: This is the speed of the projectile when it leaves the barrel of the cannon. Mass: This is the mass of the projectile. This is only a factor if air resistance is selected. Diameter : This is the diameter of the projectile. This is only a factor if air resistance is selected. Initial Position : You can control the initial position ( x and y ) by dragging the cannon with the mouse. You can measure the height by using the tape measure icon. Air Resistance : There is a check box for air resistance. For this activity, make sure the box is not checked. Air resistance will be ignored for this activity. Changing the initial conditions will affect the following variables, which are indicated in windows at the top of the simulation’s screen: Range : This is the horizontal distance measured from the launch position to where the projectile lands on the ground, or at the point where y = 0. The y coordinate for the projectile’s landing point is fixed in the simulation, but the target icon can be moved to any position on the screen. Height : This is the vertical displacement from the launch position. The simulation briefly displays the height of the projectile at 1-second intervals. To find the maximum height, use the tape measure icon. Time : This is the total time of flight of the projectile from time of launch to time of impact; black crosses indicate the location of projectile along the trajectory at 1-second intervals. Fire : This button launches the projectile. Erase : This button clears the trajectory paths off the screen. Zoom : There are two magnifying glass icons that allow you to zoom in and out. 1. Open/Access the projectile motion PhET simulation module located at: https://phet.colorado.edu/en/simulation/projectile-motion 1. Take some time to locate and become familiar with the controls. 2. Set the initial conditions to those listed in Table 2. 3. Complete Table 2 by changing the height of the launch and recording the data for range, maximum height, and time. Note: The angle, initial speed, mass, and diameter of the projectile can be entered using the keyboard. To set the initial height of the projectile, measure the height from the ground with the tape measure, then move the cannon to that height with your mouse. To measure the maximum height, use the tape measure and measure from the height of the cannon vertically to the highest point on the curve drawn by the simulator. To measure the range, measure from the position of the cannon horizontally to the curve. 4. Set the initial conditions to those listed in Table 3. 5. Complete Table 3 by changing the angle of launch and recording the data for range, maximum

Table 3 Variable: Launch Angle Trial Initial Height (m) Mass (kg) Diameter (m) Initial Speed (m/s) Angle (°) Projectile Range (m) Height (m) Time (s) 1 1 7.3 0.25 20 0 Bowling Ball 9.03 1 0.45 2 1 7.3 0.25 20 10 Bowling Ball 18.27 1.61 0.93 3 1 7.3 0.25 20 20 Bowling Ball 28.72 3.38 1.53 4 1 7.3 0.25 20 30 Bowling Ball 36.97 6.1 2.13 5 1 7.3 0.25 20 45 Bowling Ball 41.75 11.19 2.95 5 1 7.3 0.25 20 50 Bowling Ball 40.98 12.96 3.19 7 1 7.3 0.25 20 60 Bowling Ball 35.88 16.29 3.59 8 1 7.3 0.25 20 70 Bowling Ball 26.57 19 3.88 9 1 7.3 0.25 20 80 Bowling Ball 14.12 20.77 4.07 10 1 7.3 0.25 20 90 Bowling Ball 0 21.26 4.13 Activity 2: PhET Simulation Data Table 4 Table 4 Variable: Initial Speed Trial Initial Height (m) Mass (kg) Diameter (m) Initial Speed (m/s) Angle (°) Projectile Range (m) Height (m) Time (s) 1 1 7.3 0.25 5 0 Bowling Ball 2.26 1 0.45 2 1 7.3 0.25 10 0 Bowling Ball 4.52 1 0.45 3 1 7.3 0.25 15 0 Bowling Ball 6.77 1 0.45 4 1 7.3 0.25 20 0 Bowling Ball 9.03 1 0.45 5 1 7.3 0.25 25 0 Bowling Ball 11.29 1 0.45 6 1 7.3 0.25 30 0 Bowling Ball 13.55 1 0.45 Activity 2: Questions

1. For Table 2, the initial speed and launch angle were kept constant, and the height was increased. Your data should show that the horizontal range of the projectile increased with each trial. If the initial speed and launch angle were constant, how did increasing the height change the horizontal range? The increasing height made the horizontal range further because the object had more time to fall, so there was more time spent in the air. The more time in the air with the same velocity caused the ball to travel further. 6. For Table 3, the height and initial speed were kept constant, and the angle was increased. How did the launch affect the range? How did the launch angle affect the time of flight? The launch angel made the ball travel further up until 45 degrees, when the ball then stopped going further. The higher the launch angle the longer the ball stayed in the air and the higher it went. 7. Examine the data in Table 3. You should see that several angles have the same or nearly the same horizontal range. What do you notice about these pairs of angles? What is different about the trajectories of the projectiles when fired from these angles? Similar angles will have similar maximum horizontal distances. The trajectory starts off flying up and outwards, 8. For Table 4, the launch angle and height were kept constant, and the initial speed was increased. You should have noticed that the time of flight was constant as well. What does that say about two- dimensional motion? That it will fall at the same rate due to the gravitational forces acting upon it. 9. How could the speed of the projectile be determined from test-firing the cannon? By the maximum horizontal distance it goes as well as the time it takes for the projectile to hit the ground.