Projectile Motion at an Angle || Grade 9 Physics || Physics Notes

In this lesson on projectile motion at an angle, we discuss what happens to the projectile's range and maximum height as its release angle varies.

Link to youtube video: https://www.youtube.com/watch?v=g9K2zE23gGQ&t=9s

1. PROJECTILES LAUNCHED AT AN ANGLE (Nonhorizontally launched Projectile) PRESENTED BY SUJHS PHYSICS TEACHERS GRADE 9 PHYSICS

2. Learning Targets I can describe the horizontal and vertical motions of a projectile. I can investigate the relationship between the angle of release and the height and range of the projectile.

3. PROJECTILE MOTION Motion of an object that has an initial horizontal velocity and acted upon by gravity (Neglecting air resistance) Horizontal velocity is always constant Vertical velocity decreases as the projectile moves up and increases while it moves down along its trajectory Velocity Horizontal acceleration is always zero Vertical acceleration is always equal to the acceleration due to gravity, -9.8 m/s 2 (on Earth) Acceleration Horizontal distance – range Vertical distance – maximum height Distance

4. PROJECTILES LAUNCHED AT AN ANGLE (Nonhorizontally launched Projectiles)

5. The horizontal velocity always remains the same. Projectile Motion PhET Simulation PROJECTILES LAUNCHED AT AN ANGLE The vertical velocity changes at constant acceleration due to gravity (g = - 9.8 m/s 2 ). The initial velocity of a projectile is broken into its horizontal & vertical components. Due to its horizontal & vertical components, a projectile launched at an angle follows a parabolic trajectory.

6. THE HORIZONTAL & VERTICAL COMPONENTS OF PROJECTILE MOTION 29.4 m/s 2 m/s 9.8 m/s 0 m/s 2 m/s 2 m/s 2 m/s 2 m/s 2 m/s 19.6 m/s 2 m/s - 29.4 m/s - 19.6 m/s - 9.8 m/s From the point of release, its vertical velocity decreases until it becomes zero when it reaches its maximum height From the maximum height, its vertical velocity increases until it hits the ground. Note: The negative sign indicates its downward direction.

7. Projectile Motion PhET Simulation As the angles increase towards 45 degrees, what happens to the range of the projectile? As the angles increase from 45 degrees to 90 degrees, what happens to the maximum height of the projectile? What angle of release results to the longest range? PROJECTILES LAUNCHED WITH THE SAME INITIAL VELOCITY AT DIFFERENT ANGLES

8. PROJECTILES LAUNCHED WITH THE SAME INITIAL VELOCITY AT DIFFERENT ANGLES Angles of release closer to 45° result in longer ranges. The angle of release equal to 45° results in the longest range. 25° 30° 40° 45° 50° Projectile Motion PhET Simulation

9. Angles of release closer to 90° result in higher maximum heights. PROJECTILES LAUNCHED WITH THE SAME INITIAL VELOCITY AT DIFFERENT ANGLES Projectile Motion PhET Simulation 45° 60° 70° 80° 90°

10. 60° 30°

11. 50° 40°

12. 65° 25°

13. PROJECTILES LAUNCHED AT AN ANGLE (Given the same initial velocity) Angles of release closer to 45° result in longer ranges. The angle of release equal to 45° results in the longest range. Complementary angles of release have the same range. Angles of release closer to 90° result in higher maximum heights.

14. PROJECTILES LAUNCHED AT AN ANGLE (Nonhorizontally launched Projectile) PRESENTED BY SUJHS PHYSICS TEACHERS GRADE 9 PHYSICS

15. REFERENCES ‌Department of Education (2016). K to 12 Curriculum Guide for Science: Kindergarten to Grade 10. Retrieved from http:// deped.gov.ph /sites/default/files/page/2016/Science%20CG.pdf Moros, E.M., Avilla, R.A., Greogorio , J.B., & Pineda, M.G.F. (2018). Practical science 9. Makati City: University Press First Asia Papa, E. C. R., Moros, E.M., Pineda, M. G. P., & Gregorio, J.B. (2018). Practical Science 7. Makati City: University Press of First Asia Projectiles Launched at an Angle. (n.d.). Www.youtube.com . Retrieved April 5, 2021, from https:// www.youtube.com / watch?v =CgBpwVSS9tY&t=201s ‌