1. Day 15 Honors Physics In 2 classes: QUIZ 3 on kinematics, projectiles, vectors and graphs

2. HQ Q’S?

3. RELATING IT WEST VIRGINIA STYLE What major physics idea so far is always going to be in either X or Y direction? GRAVITY! Its only in the Y direction! In the air: the acceleration in Y is -10m/s 2. In the air, the acceleration in X is 0. Synopsis: Since gravity pulls down, things in air won’t change speed horizontally.

4. IN DA HALL

5. CART AND BALL.. You in seats The overall motion of the ball:

6. CART AND BALL.. You on Boards XY POS VEL ACC

7. CART AND BALL.. You in seats But what if…. I threw it at a forward angle? Would time in air change? How? Would it reach the same max height? Would it land at the same place?

8. Example One: A ball rolls off a horizontal bridge at 5m/s. The bridge is 45m high above water. We will determine how far from the bridge the ball hit the water at.

9. PICTURE… with points labeled

10. Our X and Y tables:

11. Solution

12. SUMMARY Things that move HORIZONTALLY at 1 st : Don’t go up in the air Have NO Y velocity at 1 st, only X velocity

13. So now watch this clip of a bus What is wrong with this?

15. Watch Me Do One A golf ball is hit with a velocity of 24.5m/s at 35 degrees above the horizontal. Find: ◦ Both initial velocities ◦ If it ended at the same height, find the distance it landed from the start

16. First the picture AND symmetry

17. Vi in X and in Y

18. Our tables

19. Solution

20. SUMMARY I always try to identify if I have initial velocity or not. ◦ Angles? Find the initial velocities using SIN and COS ◦ Horizontally? I can assume no up/down motion…  That means there is NO Y velocity I always try to determine if a given number or thing I am solving for is HORIZONTAL or VERTICAL. I make 2 separate tables for X and Y info.

21. Now… Look at HW, make tables