DO NOW  A soccer ball which has a mass of 550 grams is kicked at an acceleration of 40m/s 2. What is the force of the football?  A car has a mass of g is sitting in a parking lot on jupiter where acceleration due to gravity is 25m/s 2. What is the weight?

NOVEMBER 21, 2011  Do Now:  WDYS/WDYT  Pg. 184  Agenda:  Do Now  LO/SC  2.5 Investigation (Model and PhET)  2.5 Physics Talk  Learning Objective:  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  phET  ulation/projectile-motion ulation/projectile-motion  Write observations about how the angle changes the vertical and horizontal distance of the cannon ball.

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

 The shape of a projectile is a parabola. A 45 degree angle produces the maximum range of a projectile. Objects launched at less than 45 degrees have more horizontal motion than vertical motion. Objects launched at angles greater than 45 degrees have more vertical motion and less horizontal motion.

NOVEMBER 28 HW: 2.5 PTG #1-3, 6, 8, 9 DUE TUESDAY  Do Now:  Explain why a 45º angle produces the maximum range of a projectile.  Agenda:  Do Now  LO/SC  2.5 Investigation (Model and PhET)  2.5 Physics Talk  Learning Objective:  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

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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 air a long time.

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 pg 194 #1-9,

DO NOW  WDYTN Pg 192

QUESTIONS-USE GUTAU  A ball with a initial velocity of zero is dropped from a rooftop above the ground. After 3seconds the ball strikes the ground below the rooftop. How fast is the ball traveling when it HITS the ground?  How far will the ball have fallen in these 3 seconds?

 A truck drives off a cliff with a initial velocity of 0 m/s. After 4 seconds the truck strikes the ground. How fast is the truck traveling when it hits the ground?  How far will the truck have fallen in these 4 seconds?