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Days 1 thru 3. Projectile Motion. Unit 4 Class Notes. Accelerated Physics. Day #1. Free-Falling Object Review. In-Class Practice. In-Class Practice. In-Class Practice. In-Class Practice. In-Class Practice. In-Class Practice. In-Class Practice. Day #2. Horizontal Projectiles.
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Days 1 thru 3 Projectile Motion Unit 4 Class Notes Accelerated Physics
Day #1 Free-Falling Object Review
Day #2 Horizontal Projectiles
Horizontal Projectiles • The first example on the previous slide is often called a horizontal projectile. This is the first example we will look at. • The object is given an initial horizontal velocity. Thus, velocity is purely horizontal (no y component) • Our initial velocity in the y direction viy=0. • Next, analyze the motion in the horizontal and vertical direction separately.
Figure #3 Figure #2 Figure #1 From Reading Assignment handout
Using figures from previous slide • Figure 1 – Free fall object. The object’s position after every second of falling is shown. The object is accelerating because it travels a longer distance in each successive time interval. • Figure 2 – Horizontally traveling object at a constant velocity. Acceleration equals zero so each time interval shows the same distance traveled. • Figure 3 – A combination of both these motions. When a projectile falls, it accelerates downward so its y direction matches figure 1. However, since nothing (including air) slows the object down as it moves horizontally, its x direction matches figure 2.
Since projectile motion is a combination… • We will analyze the motion separately. The only shared variable between the two motions is TIME (since they both occur in the same amount of time) • Solve for time in vertical (y) side, then plug in to horizontal side.
There are so few equations in the x direction because a=0 so velocity is constant. • In the y direction we have the 4 familiar acceleration formulas. • EXAMPLE 1: A ball is rolled off a flat roof hat is 30 m above the ground. If the ball’s initial speed is 15 m/s, find the time needed to strike the ground as well as the distance that it lands away from the building. Horizontal (x) Vertical (y) From Reading Assignment handout
Horizontal (x) Vertical (y) From Reading Assignment handout
Horizontal (x) Vertical (y) From Reading Assignment handout
Day #3 COMPETITION LAB!!!! (Ball Rolling Off Table)
Day #4 Tracking and Impact Velocity
Side-ways Toss (Gravity Turned Off) Each position corresponds to 1 sec later than the previous position (starting with the red dot)
Side-ways Toss (Gravity Turned Off) Horizontal Projectiles Free-Fall
Impact Velocity Side-ways Toss (Gravity Turned Off) Horizontal Projectile Free-Fall Velocities
Impact Velocity Vfx q Vfy Vimpact
Horizontal (x) Vertical (y) 4 m/s 19.6 m/s V2 V2 = 20 m/s [78.46o BH] From Reading Assignment handout
Day #5 Angled Projectiles on Flat Ground
What we’ve done so far What we still need to do
Side-ways Toss (Gravity Turned Off) Throw-up, then Free-Fall Projectiles at Angles
So, what are the Equations we use for this “NEW” type of projectile???? Horizontal Vertical There are NO NEW EQUATIONS
vi viy q vix vi So…..How are “angled” projectiles different than “horizontal” projectiles? q Viy = 0 (for horizontal projectiles) = visinq Viy = something, + or - (for horizontal projectiles) = vicosq
q Vix = Vfx = Vx = 0 (since ax = 0) Vy, top = 0 When rising, Vy is positive (when falling = Vy is negative) The velocity at every moment in time is the resultant of the two velocity components If launching and landing occurs at the same height (on level ground) then the launching/landing speeds & angles are the same What are some important things to remember? vi q
Day #6 MORE Angled Projectiles … Sometimes NOT on Flat Ground