Today I will: Define projectile Explain projectile motion in terms of horizontal and vertical motion

Ch 3 Part 2:Projectile Motion

Review some vocab…. Free Fall Gravity When an object moves through the air with ONLY gravity acting on it (limit AR) Gravity A downward force (pull) on an object toward the Earth (this pull causes objects to accelerate at a rate of -9.8 m/s2)

New Vocab… Projectile Any object in free fall (remember in free fall object can be moving up or down)

Motion of Projectiles Projectiles have motion in 2 – d the d in 2d means dimension The two dimensions are the two components of motion

Projectile Motion A projectile is an object moving in two dimensions under the influence of Earth's gravity; its path is a parabola.

2 Components of Motion Vertical and Horizontal

Projectile Motion It can be understood by analyzing the horizontal and vertical motions separately.

Vertical Component (y) what is happening on the y-axis only; example: how high an object goes or how far down it falls At the objects highest point its vy = 0 ; no longer moving upward Since gravity acts downward it acts on the y-axis…causes object to gain or lose speed going up and coming down (a = -9.8m/s2 )

Horizontal Component The movement in the x (horizontal direction) Gravity DOES NOT act on the horizontal since it only acts downward The object will not accelerate in the horizontal direction

Horizontal Component Summed UP…. The object will have a constant vx! The vx will be the same at all points during the objects flight!

The vertical and horizontal components are independent of one another Time is the link between the components The time of the flight is the same for the x and the y

Projectile Motion It can be understood by analyzing the horizontal and vertical motions separately.

in the y-direction the object moves with constant acceleration g. The ball on the right has an initial velocity in the x-direction; this velocity remains constant in the y-direction the object moves with constant acceleration g. NOTE: vertical positions of the two balls are identical at identical times. two balls start fall at same time.

Ideal vs actual path Ideal Path – path an object would follow if gravity did not exist (straight line) Actual Path – path object follows because gravity exerts a force on the object

Ideal Path

Ideal vs Actual

Ideal vs Actual Shooting Upward

Monkey and Hunter http://www.physics.umn.edu/video.html?url=/media/outreach/pforce/circus/videos/MechanicsProjectileMotion-MonkeyAndHunter.flv&vidname=Physics%20Force:%20Monkey%20and%20Hunter&goback=/outreach/pforce/circus/

Understanding Projectile Motion

Finding X and Y components

Ideal path – straight line path with out gravity and Actual Path – curved path with gravity Angles of launch:

Concept Development 3-1

CDP for Projectiles

Using Vectors for Projectiles Got to the back of the third page in Blue CDP

Angles of Launch Pre-Lesson Question: What angle do you think you would have to throw something for it to go the highest? What about to have the longest range (horizontal distance)?

Angles of launch: Complimentary Angles: two angles that add up to 90⁰ Have the same horizontal range To go the highest – throw straight up (90⁰) To go the furthest – throw at 45⁰

Projectile Motion - Cannon http://phet.colorado.edu/sims/projectile-motion/projectile-motion.swf

Solving Problems Involving Projectile Motion SEE HANDOUT

Solve projectile motion problems Today I will: Opening: Solve projectile motion problems Define satellite Pick up yellow packet and have out blue packet from Friday How are the vertical and horizontal component of motion related?

satellite – fast moving projectile a projectile that is moving fast enough that it falls around the Earth (follows the curve) rather than into the Earth (it is still acted on by gravity); goes beyond the Earth’s atmosphere to a height of about 150 km (where there is almost no air resistance) An object would need a speed of 8 km/s to escape Earth’s atmosphere

Equations for Projectile Motion Vertical component of motion…has acceleration Can use our kinematic equations vyf = vyi + at ∆dy = vyit + ½ at2 vyf2 = vyi2 + 2a(∆dy)

Horizontal component of motion: no acceleration (why?) 𝑉 𝑥 = 𝑑 𝑥 𝑡

Problem Set Up Time = dx = Vyi = Vx = a = -9.8 m/s2 ∆dy = Vyf =

Problem Solving: Melanie Rolls a 10g marble down a ramp and off the table with a horizontal velocity of 1.2 m/s. The marble falls in a cup placed 0.51m from the table’s edge. How high is the table?

Book Work! page 41 TE 34-38  

Period 6 Pick up lab packet from front desk! Check book work answers that are on the board!! You need to do this NOW! Today We Will: prelab; you look over answers and ask questions; show me the equation or equations your group plans on using to solve for placement of the target Tomorrow: period 6 set up and do lab! Period 7: finish lab; ask any additional questions you may have

Period 8 Have lab packet out from Thursday NOW!! Pick up ans packet and sheet from front student desk! Today We Will: pre-Lab; you look over answers and ask questions; show me the equation or equations you need to find dx Tomorrow: set up and do lab! finish lab; ask any additional questions you may have on projectile motion problems

prelab 1. find vx use distance of flat track and time on flat track! Once you find vx Forget you have a d and t!! You no longer need them (only need to find vx) 2. height of table 3. computations: you now have vx , vyi , ∆dy and acceleration. You need to find dx. Solve as you would any projectile motion problem! Show me the equation! Turn in ball Get target