EXAM NEXT CLASS All through Day 1 of GT physics.

A Reminder Which is the correct for the Y component of this vector? A) 20 Sin 30 B) 20 Cos 30 C) 30 Sin 20 D) 30 Cos 20

YOU AND GOLF BALLS… I created a free response type prompt to help you understand the ideas of yesterday as well as what to expect.

ALONE AT FIRST… PART 1 11 minutes for all 3 is expected from you.

OK… Talk over 1-3 with Partners 7 minutes

Example of Grading Style 7 points total A) 2 points: 1 point: For a procedure that could correctly be used to verify the two goals of initial velocity and angle 1 point: For the measurements that needed to be made: Time in air from launch to FIRST impact The height AND horizontal distance from initial point to first impact

B) 2 points: 1 point: For correct indication of how the measurements can be used to determine the initial velocity. Must include using the Pythagorean theorem OR tangent of a known angle. 1 point: For correct indication of how the measurements can be used to determine the launch angle. Must include using the Pythagorean theorem OR tangent from the X and Y components of the initial velocity.

C: 3 points. 1point: Correct X graphs showing a linear position relationship AND a velocity at a positive value but zero slope. 1 point: Correct Y graphs showing a parabolic arc ending at a lower position than starting AND a velocity with a negative slope starting positive and ending at a larger negative value. 1 point: Correct description for the graphs.

NOW TRY.. THE ACTUAL PART 4

Part 5… I show

DO YOU GET IT? Max height relationship

DO YOU GET IT? Overshooting….

Or in Other Words…lets write V’s at points

Highest point: A system minimum velocity because Vy is minimized (at top of arc Vy is 0) Symmetry: The velocity up at any height going up has = Vx and = but opposite Vy of the same height going down (ignoring…) So lets turn to the 3 problems that I will teach

MAJOR IDEA: For any object at some height with an initial velocity, changing the angle will not affect the velocity of impact! In words:

2) A girl throws a rock horizontally with a velocity of 10m/s from a bridge. It falls 20m to the water below. How far does the rock travel horizontally before striking the water?

Key Projectile Terms/Strategies Horizontal initial motion implies: Separate numbers and values into X and Y to use Accelerations for X and Y, and time:

Lets Try the Misconceptions…