HW PTG 1 3 6 8 9 WELCOME

HW: PTG #1 -3, 6, 8, 9 WELCOME TO CLASS! Learning Objective: Do Now: WDYS/WDYT Pg. 184 Agenda: Do Now LO/SC 2. 5 Investigation (Model and Ph. ET) 2. 5 Physics Talk Explain the shape of a projectile’s motion and how it relates to the object’s range Compare horizontal motion to vertical motion in projectile motion Success Criteria: Use mathematical models of free fall and uniform speed to construct a physical model of the trajectory of a projectile Use the motion of a real projectile to test a physical model of projectile motion Use a physical model of projectile motion to infer the effects of launch speed and launch angle on the range of a projectile

INVESTIGATION 2. 5 Tennis ball thrown along wall at a model What happens if we change the angle? Does the tennis ball still follow the trajectory?

SHOOTING A CANNON BALL ph. ET http: //phet. colorado. edu/en/si mulation/projectile-motion Write observations about how the angle changes the vertical and horizontal distance of the cannon ball.

LAUNCHING A CANNON BALL Angle Range Height “Hang Time” 15˚ 30˚ 45˚ 60˚ 75˚ Yes, you must really copy this in your journal

PHYSICS TALK 2. 5 What is a projectile? How many motions does a projectile have and what are they? A fired, thrown, or otherwise propelled object, such as a bullet, having no capacity for self-propulsion There are two kinds of motion – vertical and horizontal. Example: horizontal speed of launch penny and verical fall due to gravity

PHYSICS TALK 2. 5 What is the shape of the path of all trajectories? A parabola

PHYSICS TALK 2. 5 What does the trajectory look like when you launch a projectile from different angles?

PHYSICS TALK 2. 5 What observations can be made about the previous diagram? All balls travel in parabolas The 45˚ launch angle produces the greatest range (largest distance) The distance traveled at pair angles is identical (ex. 30˚ and 60˚, 20˚ and 70˚, 10˚ and 80˚) Small angles have greater horizontal velocities but are in the air a short time Large angles have smaller horizontal velocities but are in the

PHYSICS TALK 2. 5 What is being ignored in all of the diagrams that might make the actual occurrence look different? In sports, we often have air resistance. This will provide a force against gravity that may cause a projectile to stay in the air longer than the models show.

WHAT DO YOU THINK NOW? Now that you have completed the experiment and taken the notes, answer the WDYTN questions on page 192 in your journal.

HOMEWORK HW: PTG #1 -3, 6, 8, 9