Projectile motion and V f vertical velocity Tuesday, December 2, 2014

Monday, 12/1 Unit 5: Projectile Motion  Pick up warm-up from the ‘Physics bin’  Make note of upcoming dates below.  Warm-up question for today is on your warm-up sheet.  Upcoming dates  Thursday, 12/4 – Projectile motion quiz  Thursday, 12/4 – exemption window opens  Thursday, 12/4 – Review due when the late bell rings  Monday, 12/8 – Projectile motion test  Wednesday, 12/10 – exemption window closes  Friday, 12/12 – 3SW extra credit due  Thursday, 12/18 – 5 th period final: 11:25 am to 12:45 pm  Friday, 12/ th period final: 11:25 to 12:45 am  Friday, 12/19 – end of the semester

Warm-up Use the graph to the left to answer the questions below. 1.What value is represented on the y-axis? 2.What value is represented on the x-axis? 3. In order to maximize the range of the projectile, the object should be launched at ______ degrees.

Horizontal Projectile  What we know  A projectile has two dimensions to it’s motion.  Horizontal  Vertical  The initial velocity (V i ) in the horizontal is a value that is given to us or we can calculate it.  The initial velocity (V i ) in the vertical is always zero.

Horizontal Projectile  What about Final Velocity?  Watch animation mmedia/qt/vectors/prehlp.cfm

Horizontal Projectile – Velocity  Horizontal Velocity  There is no force acting on the object horizontally therefore inertia applies and the horizontal velocity remains constant.  There is no change in velocity therefore there is no acceleration.  What do you think the final horizontal velocity would be just before it hits the ground?

Horizontal Projectile – Velocity  Vertical Velocity  When the projectile is launched there is no initial vertical velocity.  After the projectile is launched the force of gravity starts to have an affect on the vertical motion of the object.  The objects starts to accelerate (velocity is changing).  The velocity starts to increase.  What do you think the final vertical velocity of an object would be just before it hits the ground?

Final Velocity Example: Use the information in the table to calculate final velocity. Horizontal Velocity Vertical Velocity ∆x = 9.2∆y = m V i = 6 m/sV i = 0 m/s a = 0 m/sa = 9.8 m/s t = 1.53 s

Practice with your elbow partner

Horizontal Projectile Explore k12.org/cms/lib4/TX /Centricity/Do main/2851/Linear Motion/2D Motion/Mythbusters Bullet Drop.wmv

Project

Review