Projectiles

2-D Motion

Now we have movement in both x & y dirs.

Gravity acts down vy changes

No force horizontally vx is constant

Steps

1. Separate everything into x & y columns only time can pass between the columns a = -9.8 m/s2 in y-direction

2. Write all givens in correct columns separate vo into vox and voy

3. Write equations 3 Amigos in the y-direction v=Δs/t in the x-direction

4. Solve

A cannon is fired with vo = 40 m/s at a 30° upward angle. How far away does it land?

vo

θ

____x____ ___y___

A cannon is fired with vo = 40 m/s at a 30° upward angle. How far away does it land?

vo

θ

____x____ ___y___

Tips

Horizontal projectiles have θ = 0° At the peak, vy = 0 If it starts and ends at the same level:

vfy = -voy Δy = 0 at the peak t = ½ the total travel time

vox = vfx = vx everywhere