3/15/11

Post date: Mar 15, 2011 12:55:18 PM

• • Bell Ringer: Why was projectile motion one of the earliest "sciences" to be studied?

  • Discuss final projects

  • Projectile Lab

    • Goal: find the angle that gives the largest range (dx) for a ping pong projectile, determine the relationship between range and angle, collect enough data to accurately hit a target with the projectile

    • Procedure: Launch ping pong balls at various angles (multiple times for each angle) to determine the relationship, try numerous trials in area of greatest range to determine a precise angle for the maximum range.

    • This is a full lab write-up, due Monday, 3/21

  • Intro to projectile motion

    • Has a horizontal and vertical component

    • Projectile - an object moving through space horizontally and vertically with gravity being the only force acting on it

    • Vertical motion and horizontal motion don't affect each other (a falling bullet hits the ground at the same time as a bullet shot horizontally)

    • Can use all the chapter 4 equations, but now in X or Y directions

  • Given information:

• • Equations:

    • Vfx = Vix + (ax)(t), Vfy = Viy + (ay)(t)

    • dx = 1/2 (Vix + Vfx)(t), dy = 1/2 (Viy + Vfy)(t)

    • dx = (Vix)(t) + 1/2(ax)(t^2), dy = (Viy)(t) + 1/2(ay)(t^2)

    • (Vfx)^2 = (Vix)^2 + 2(ax)(dx), (Vfy)^2 = (Viy)^2 + 2(ay)(dy)

    • t is the same for both x and y

    • acceleration in the x direction is zero (no horizontal forces), acceleration in y direction is -9.80 m/s/s .

    • vi and vf in the x direction will be the same (horizontal velocity is constant)