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# P rojectile

P rojectile. An object that is launched by a force and continues to move by its own inertia. The only force acting on it is gravity. (in free fall). http://www.physicsclassroom.com/class/vectors/Lesson-2/What-is-a-Projectile. Trajectory. The path that a projectile traces.

## P rojectile

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### Presentation Transcript

1. Projectile • An object that is launched by a force and continues to move by its own inertia. The only force acting on it is gravity. (in free fall) http://www.physicsclassroom.com/class/vectors/Lesson-2/What-is-a-Projectile

2. Trajectory • The path that a projectile traces.

3. 4 Types of Projectile Motion • Dropped (straight down, (a = g) • Trajectory is straight line down • vy = gt http://www.physicsclassroom.com/class/1DKin/Lesson-5/Acceleration-of-Gravity

4. 4 Types of Projectile Motion • Dropped (straight down, a = g) 10.00 3.80 1.80 0.00 -9.8 m/s2 http://mmsphyschem.com/putTo.htm

5. Dropped vs Thrown Straight Down Dropped Thrown time time velocity velocity slope = g (both) and vf = vi + gt

6. 4 Types of Projectile Motion 2. Launched straight up (then falls down, a = g) • Trajectory is a straight line up & down • video -9.8 m/s2 -9.8 m/s2 -9.8 m/s2 http://www.vias.org/physics/bk1_05_03.html

7. 4 Types of Projectile Motion 2. Launched straight up 3.80 1.80 0.00 -9.8 m/s2

8. 4 Types of Projectile Motion 3. Launched horizontally(a = g) • Trajectory is half a parabola https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwj2gq7-mLXPAhUF4SYKHS1_BKwQjRwIBw&url=http%3A%2F%2Fwww.physicsclassroom.com%2Fclass%2Fvectors%2FLesson-2%2FHorizontally-Launched-Projectiles-Problem-Solving&psig=AFQjCNELCE2OC_vCsuYCUpZUg7PfH7-UJQ&ust=1475259683571516

9. 4 Types of Projectile Motion Horizontal Velocity 3. Launched horizontally, cont 3.80 1.80 0.00 Vertical Velocity -9.8 m/s2

10. 4 Types of Projectile Motion 3. Launched horizontally, cont. • Independence of horizontal and vertical motion • Only when they act in concert do we get a true parabolic trajectory • Motion equations can be used in one dimension only

11. 4 Types of Projectile Motion 3. Launched horizontally • Equations • Since velocity does not change in x direction, our average velocity equation works…vx= dx/t • vy= viy+ at • dy = viyt + .5at2

12. Sample Problem A stone is thrown horizontally from the top of a cliff with a velocity of 15 m/s. It takes 3 s for the rock to land. a) How high is the cliff? b) How far from the base of the cliff does the stone strike the ground?

13. Sample Problem, cont. A stone is thrown horizontally from the top of a cliff with a velocity of 15 m/s. It takes 3 s for the rock to land. a) How high is the cliff?

14. Sample Problem A stone is thrown horizontally from the top of a cliff with a velocity of 15 m/s. It takes 3 s for the rock to land. b) How far from the base of the cliff does the stone strike the ground?

15. 4 Types of Projectile Motion 3. Launched horizontally Cliff Diving on Mars vx v = vx2 + vy2 vy v

16. 4 Types of Projectile Motion 4. Launched at an angle (a = g) What do you notice about the - vertical motion?- horizontal motion?

17. 4 Types of Projectile Motion 4. Launched at an angle, cont… • Horizontal velocity • Vertical velocity

18. 4. Launched at an angle (cont)… • acceleration

19. Kinematics of Projectile Motion

20. Draw position vectors http://www.physicsclassroom.com/reviews/vectors/vectorsprint.cfm

21. Draw acceleration vectors a = -9.8 m/s2 a = -9.8 m/s2 a = -9.8 m/s2 a = -9.8 m/s2 a = -9.8 m/s2 a = -9.8 m/s2 EVERYWHERE!!! a = -9.8 m/s2 a = -9.8 m/s2 http://www.physicsclassroom.com/reviews/vectors/vectorsprint.cfm

22. Draw velocity component vectors vy vx vy vx vx vy vy vx vx vx vy http://www.physicsclassroom.com/reviews/vectors/vectorsprint.cfm

23. Actual velocity resultant vectors v vy vx vy vx vx vy v vy vx vx v vx vy http://www.physicsclassroom.com/reviews/vectors/vectorsprint.cfm

24. Projectile Motion Summary Object has: • Horizontal Uniform motion • Vertical Acceleration due to Gravity affects motion

25. Question? Suppose a rescue airplane drops a relief package while it is moving with a constant horizontal speed at an elevated height. Assuming that air resistance is negligible, where will the relief package land relative to the plane? a. below the plane and behind it.b. directly below the plane c. below the plane and ahead of it http://www.physicsclassroom.com/mmedia/vectors/pap.cfm

26. Another Question? Anna Litical drops a ball from rest from the top of 78.4-meter high cliff. How much time will it take for the ball to reach the ground? It will take 4 seconds to fall 78.4 meters

27. Worksheet

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