1. Warm-Up
What are the two main categories of forces?

2. What exactly is a Force A force is a push or pull on an object Recall:
A force can act though contact
Spring, normal, applied, friction, etc
A force can act a distance
Gravity, magnetism, electrical

3. Vectors
Magnitude and Direction:

4. http://www.nbclearn.com/portal/site/learn/science- of-nfl-football
Projectile Motion
of-nfl-football

6. Projectile Motion
Only one force is acting on an object during projectile motion – gravitational force
Often air resistance is negligible
Object follows a parabolic path

7. Projectile Motion
Another way to define projectile motion is horizontal and vertical motion that is independent of one another.
Why is that important?
It means we can look at each direction individually

8. Horizontal Motion No external forces acting in horizontal direction.
This means: constant velocity

9. Vertical Motion Gravitational force will pull the object down.
Direction of this force is from the direction of acceleration, which is directed down.
Eventually, the projectile will reach a vy = 0 m/s.
This occurs at the maximum vertical height.
After this, the ball begins to accelerate in the downward direction.

10. Vertical Motion
Increasing velocity in downwards direction:

11. Putting it all together
The path of the projectile cannot change its path without introducing a new force.
Training must prepare an athlete to accurately set the projectiles path just before release.
NBC – Nick Goepper & the Physics of Slopestyle Skiing

12. PROJECTILE RAMP CHALLENGE
Day 2

13. Projectile Motion Challenge
Remember:
Your ramp must be able to be set at 4 different angles: 15o, 30o, 45o, 90o.
Once you have finished building your projectile launcher, you will measure its horizontal distance at each angle.
You will need to make 3 different measurements at each angle.

14. Ramp Challenge Per Group: Per Person: Ramp
Sketched design of your ramp
Per Person:
Data Table
Answers to questions
Pre-Lab Question:
Which angle do you predict to have the greatest horizontal displacement?

15. Questions
Did your final design differ from your initial sketch? If so, explain the difference AND make a sketch of your final design.
Which angle launched the marshmallow the farthest horizontal distance?
Which angle do you think produced the greatest vertical height?
What other variables could have been introduced during this experiment? If your results showed an angle besides 45 degrees for farthest distance, then what could have been your error?

16. 3 Concerns with Projectiles
Time of flight
Peak height
Horizontal displacement
Which sports are concerned with time of flight? Peak height? Horizontal displacement?.

17. Simulation
motion/projectile-motion_en.html
Think of our three major concerns with projectile motion
Time in flight
Peak height
Horizontal displacement

18. Time in flight Depends on: Optimal angle of projection: 90o
Physics
Sports
Depends on:
Initial vertical velocity
Initial vertical position
Optimal angle of projection: 90o
Above 45o
Maximize Time:
Gymnastics
Figure Skating
Ski jumping
Snowboarding (half-pipe)
Minimize Time:
Volleyball spike
Tennis smash
PK kick – soccer
Baseball throws

19. Peak Height Depends on: Optimal angle of projection: 90o High Jump
Physics
Sports
Depends on:
Initial height
Initial vertical velocity
Optimal angle of projection: 90o
Greater than 45o
Larger angle = larger vertical velocity
High Jump
Volleyball
Basketball

20. Horizontal Displacement
Physics
Sports
Depends on:
Initial horizontal velocity
Time in flight:
Initial vertical velocity
Initial height
Optimal angle of projection:
45o  there are equal x & y components
Smaller angles are required if initial height is present.
Harder to produce vertical motion than horizontal
Shot put
Discus throw
Long jump
Baseball hit
Imagine a bowling ball – is it easier to roll it horizontally or throw it up in the air?

21. Applications In Sports
Golf – Long Irons (1,2, 3) have a shallow angle on the club face. They are designed for distance. Short irons (7, 8, 9, wedge) have steeply angled faces to give height and “stopping” ability when the ball lands.

22. Biomechanics
Speed of release can be maximized in order to gain distance or time in flight by applying biomechanical principles such as transfer of momentum, sequencing and lengths of levers.
By driving with Legs  torso  shoulder  arm  hand.
The body acts like a whip imparting tremendous force to the ball.

23. Winter Olympics Project

24. Exit Ticket
What force(s) is/are acting on an object during projectile motion?
What implications does projectile motion have on sports, knowing that you can’t change the projectile’s path once it is in the air?