PHYS 125L SimulationLab#S1 ProjectileMotion

Name: Date: Lab: Projectile Motion Your Name : Benetou Mcneil Partner’s Name: ( Courtesy of the Department of Physics, University of Colorado, Boulder, Colorado ). Part -I Objective : To show that the time of flight of a horizontal projectile is independent of its initial speed. Procedures: 1. Open the following link (from PHET Simulation): https://phet.colorado.edu/sims/html/projectile-motion/latest/projectile-motion_en.html 2. Set the height at any value between (10 -15) m 3. Adjust the angle of the launcher θ at zero degree. 4. Set the velocity of the projectile at 3 m/s and fire a football of mass 0.5 kg then measure the time of flight (T) at the point where the football hits the ground. 5. Repeat the previous step for four more different values of velocity as shown in table 1 and measure the corresponding time (T). 6. Report your data in Table (1). 7. Repeat the same in the presence of air resistance.

Name: Date: v (m/s) Time of flight (T) s without any air resistance Time of flight (T) s in the presence of air resistance 3 1.75 1.85 6 1.75 1.85 9 1.75 1.85 12 1.75 1.85 15 1.75 1.85 Table (1) 8. Does the time of flight depend on the initial speed of the flight? No matter what the velocity of the object is, it will always hit the ground in the same amount of time because it is free falling. 9. Does the air resistance change the range, how? Part II Objective :  To study the relationship between the angle of the projectile with its angle.  T o find the acceleration of gravity g exp . Procedures: 1. Open the same link: https://phet.colorado.edu/sims/html/projectile-motion/latest/projectile-motion_en.html 2. Click on Lab. 3. Leave the settings to the right of the screen as they are. 4. Set the initial speed at 15 m/s. 5. Adjust the launcher at 25 o. 6. Click on the red button below and release the projectile. 7. Move the red circle horizontally toward the projectile target and measure the range R. 8. Record the angle (θ) and the range (R) in table 2 in your lab report. 9. Repeat steps 6-8 for the angles (30 o , 35 o , 40 o , 45 o , 50 o , 55 o , 60 o , 65 o , 70 o ,75 o , 80 o ). 10. Calculate sin (2θ) and record that in Table 2.

Name: Date: Table (2) v o = 15 m/s θ o Sin (2θ) R (m) 25 .84 19.73 30 .87 19.87 35 .93 19.96 40 .98 21.23 45 1.00 22.96 50 .79 21.80 55 .83 20.24 60 0.87 19.91 65 0.85 17.76 70 0.64 14.72 75 0.5 11.44 80 0.48 10.59 13. Post the graphs here

Name: Date: 14. From the graph of (R-sin2θ), calculate: a) Slope = 23 b) g exp = 22.9 c) % Error in g= π 180 Now answer the following questions: 1) The trajectory of a projectile is a a) Parabola b) Circle c) Straight line d) Ellipse 2) The .......... of motion changes during the motion of a projectile. a) direction b) velocity c) direction of velocity d) All the above 3) Depending on part-II, what angle produces the biggest range? why? 45 degrees produce the biggest range because at that point the sin value is the largest. 4) What changes would occur to the time if we neglected the air resistance? If the air resistance is ignored the time will decrease in a small way. 5) What changes would occur to the range of the projectile if air resistance were to be neglected? If the air resistance was to be ignored the range of the projectile would not change much.