PH212 Lecture Notes - Lecture 7: Projectile Motion, Vix
25 Dec 2018
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1
3.1
Projectile motion is main example
Motion in horizontal and vertical directions are independent
x and y motions are independent (linked only by time).
There is acceleration in y direction
There is no acceleration in x direction – constant velocity
Above, is there acceleration in the x direction?
Without air resistance, path is a parabola
Motion is free fall but with an initial horizontal velocity
Horizontal launch: vix = vi, viy = 0
Non-Horizontal launch: vix vi ,viy 0
No change in equations of motion for either x or y components except initial y velocity is not zero
for non-horizontal
For non-horizontal launch, need to calculate initial x and y velocities from launch velocity and angle
Document Summary
Motion in horizontal and vertical directions are independent x and y motions are independent (linked only by time). There is no acceleration in x direction constant velocity. Motion is free fall but with an initial horizontal velocity. Horizontal launch: vix = vi, viy = 0. Non-horizontal launch: vix vi ,viy 0. No change in equations of motion for either x or y components except initial y velocity is not zero for non-horizontal. For non-horizontal launch, need to calculate initial x and y velocities from launch velocity and angle. Dx = v0x dt + ax (dt)2 vx = v0x + ax dt ax = 0. Double subscript notation: v0x = initial velocity, x direction. Dy = v0y dt + ay (dt)2 vy = v0y + ay dt ay = g = - 9. 81 m/s2. The equations of motion in the vertical direction are the same for the two objects. Object #1: vox = 0; voy = 0.
