Projectile motion and Vf vertical velocityTuesday, 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 – 5th period final: 11:25 am to 12:45 pm Friday, 12/19 - 8th 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 (Vi) in the horizontal is a value that is given to us or we can calculate it.

The initial velocity (Vi) in the vertical is always zero.

Horizontal Projectile What about Final Velocity?

Watch animationhttp://www.physicsclassroom.com/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 = 11.47 m

Vi = 6 m/s Vi = 0 m/s

a = 0 m/s a = 9.8 m/s

t = 1.53 s t = 1.53 s

Practice with your elbow partner

Horizontal Projectile Explorehttp://www.gcisd-k12.org/cms/lib4/TX01000829/Centricity/Domain/2851/Linear Motion/2D Motion/Mythbusters Bullet Drop.wmv

Project

Review