Post on 31-Dec-2015
description
For each diagram below, create a free diagram of the ball at the top
of the path
As you view the following video and animation think about the forces in your
free body diagrams 2-D Motion
Independence of Motion
• Notice that the veridical motion of the projected ball is identical to the vertical motion of the falling ball
• Notice that the projected ball travels forward at constant speed
Horizontal Component of Velocity
• Is constant
• Not accelerated
• Not influenced by gravity
• Follows equation: dx = Vixt + 1/2axt2
0
Vertical Component of Velocity
• Undergoes accelerated motion
• Accelerated by gravity (9.8 m/s2 down)
• Vfy = Viy + at
• dy = Viyt + 1/2ayt2
• Vfy2 = Viy
2 + 2aydy For all y-direction projectile equations
a=g
Perpendicular components of motion are independent of each other
Independence of Motion
Please visit the Physics Zone Projectile Motion Lesson “Archer in Truck: Proof III”at sciencejoywagon.com to access this video.
x y
Vi
Vf
v
v
a
d
t
This may be a useful way to organize your data. Remember to solvex variables with x variables and y variables with y variables….
TIME links the x and y variables
Projectile fired at an angle
• As you view this video, notice the independence of motion.
• Notice that the vertical acceleration is downward and constant– The ball “slows” during ascent and “speeds up” during
descent
• When angles are involved, the appropriate components of velocity must be used and the sign used to indicate the direction of velocity and acceleration is very important
A bouncing ball captured with a stroboscopic flash at 25 images per second.
MichaelMaggs Edit by Richard Bartz